Which square (A, B, C, or D) represents the repeating subunit of the polymer shown? Three dots then C connected by single lines to H above and C H subscript 3 below. Then a single line to a C connected by single lines to one H each above and below. Then a single line to a C connected by single lines to H above and C H subscript 3 below. Then a single line to a C connected by single lines to one H each above and below. Then a single line to a C connected by single lines to H above and C H subscript 3 below. Then a single line to a C connected by single lines to one H each above and below. Then a single line to a C connected by single lines to H above and C H subscript 3 below. Then a single line to a C connected by single lines to one H each above and below. Then a single line to a C connected by single lines to H above and C H subscript 3 below. Then a single line to a C connected by single lines to one H each above and below. Then a single line connecting to a C connected by single lines to H above and C H subscript 3 below. Then a single line to a C connected by single lines to one H each above and below. Then three dots. A box labeled A surrounds the first C and things connected above and below. A box labeled B surrounds the fourth C and things connected above and below. A box labeled C surrounds the seventh and eighth C's and things connected above and below. A box labeled D surrounds the last 2 C's only.