What gifted musician was heavily involved in the 1960s civil rights movement with King and Caser
Chavez?

Harry Belafonte

Explanation:

your word would be isle.

isle is an island or peninsula especially a small one.

if you add the letter "a" you get aisle, which is a passage between 2 rows of something like chairs, shelves, or something else.

all options are correct a) b) c) and d)