Monochromatic means darks of a color

A many shades of 1
B color
C lights of a color
D shiny chrome

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.

hey

he was  an italian composer who wrote 39 operas, as well as some sacred music, songs, chamber music and piano pieces.

hope this and i wish you the best of luck! : )