Which of these is a matter of "mechanics"?

a)punctuation
b)capitalization
c)spelling

The matter of "mechanics" in writing refers to the rules and conventions that govern the technical aspects of language usage. It focuses on the correct use of punctuation, capitalization, spelling, and other similar elements of writing.

Based on this definition, all of the options you provided, which are punctuation, capitalization, and spelling, are matters of "mechanics" in writing. They are essential in ensuring the clarity, accuracy, and overall effectiveness of written communication.