You've probably skimmed across thousands of lines of text without ever considering how individual letters look. Designers, in contrast, can be highly focused on minute details of fonts and type styles. Carefully examine a letter e as you read this or another text. What is the proportional size of the closed-off upper shape versus the curved "tail"? Does the end of the e's tail have a vertical, horizontal, or slanted edge? How wide is this most common of letters in relation to its lowercase neighbors?

How does the underlined sentence reinforce the main idea of the paragraph?

a. It explains the difference between a well-designed and poorly designed font.

b. It shows how very small details of letters affect how ordinary people read text.

c. It describes an extremely small detail that designers notice, but most other people don't.

b. It shows how very small details of letters affect how ordinary people read text.

The underlined sentence reinforces the main idea of the paragraph by emphasizing the importance of paying attention to minute details of letters in fonts and type styles, as even small details can affect how easily people can read and understand text. This highlights the expertise and attention to detail that designers bring to their work, in contrast to the average reader who may not notice these subtle differences.