Answer:
Focus
Explanation:
to specialize in a subject is to focus and study it.
C im not sure is is right .
The words and punctuation that best corrects any errors in the sentence is option A. well-known. The word well-known should have the punctuation mark hyphen because it is a compound word. Compound words are words that consist of two or more words linked together by a hyphen, in order to create a new word with a new meaning. The word "well-known" means famous.
