Passage:

Most people outside of Farmington, Maine, have never heard of Chester Greenwood—but endless numbers of children have a fun way to play outside in cold winter weather because of his invention. 

Chester Greenwood was born in 1858 in Farmington, Maine. One of six children, he grew up on a farm. The family raised chickens and sold eggs. Greenwood walked an eight-mile route to deliver eggs to customers. Some of them also bought the peppermints he made. 

As a teenager, Greenwood loved skating. During the winter of 1873, he was given a new pair of ice skates. The 15-year-old headed for the local pond to try them out. The winter of 1873 was bitterly cold, and soon Greenwood's ears were stinging. He wrapped a wool scarf around his head, but it was both itchy and bulky. It was hard to see, much less skate, with a scarf tied around his head. 

Most people would have given up and waited for the weather to improve, but Greenwood was unwavering in his determination to find a way to protect his ears so he could skate. He took some wire and bent it into a pair of loops. Hurrying home, he persuaded his grandmother to sew material over the loops. Greenwood chose fur for the outside and velvet for the inside, which would be next to his sensitive ears. In no time, his grandmother had finished the first earmuffs ever made. With his new invention, Greenwood could keep his ears warm while skating. 

As he glided around the ice, fellow skaters noticed the strange invention on Greenwood's head. When asked, he called them "ear mufflers." Soon everyone wanted the ear mufflers. Greenwood's mother and grandmother helped by covering the wire frames with fur. Ear mufflers were extremely successful, and in 1877, Greenwood patented a model with a steel band. He was only 18 at the time. His "one-size-fits-all" model had ear covers that could be folded to store in a pocket. Greenwood called them his "Champion Ear Protectors." 

Soon, his mother and grandmother could not keep up with the orders. Greenwood moved his business into a factory in Farmington. By the early 1880s, more than 30,000 ear mufflers were being purchased every year. By 1936, the number was near 400,000. Farmington became the "Earmuff Capital of the World." 

Greenwood did not stop inventing, though. He applied for more than 100 patents. He invented 15 machines to help make and assemble parts for the earmuffs. He also invented a steel-tooth rake, shock absorbers, a whistling teakettle, and a washing machine. Other inventions included a new type of spark plug and a folding bed. While it is a joke among inventors that each is trying to invent a better mousetrap, Greenwood actually did come up with a mechanical mousetrap. The Smithsonian Institution has named him one of this country's 15 outstanding inventors. 

In 1977, Maine's legislature passed a law declaring December 21 as Chester Greenwood Day. Farmington residents and thousands of visitors celebrate Chester Greenwood's invention on the first Saturday of December. The day features events such as an earmuff fashion show and a cold-ear contest. Best of all, there is a Chester Greenwood Day parade with its own flag: red earmuffs on a white background. Everything from police cars to cows wears earmuffs. Even the dogs wear earmuffs! 

Chester Greenwood proved that a person can be a successful inventor at any age. All Greenwood wanted to do was find a way to keep his ears warm. In doing so, he started a million-dollar industry. 
Use the selection to answer the question.
Who or what is the subject of this selection?

A.
Farmington, Maine

B.
Chester Greenwood

C.
winter

D.
earmuffs

The answer is obvious. What is it?

I copy pasted wrong question.

And B. :/

Yes, b.

The subject of this selection is B. Chester Greenwood.