Acrilan is a hard, horny and a high melting material. Which of the following represents its structures?
A. `[-CH_2-CH_2-overset(CN)overset(|)CH-]_n`
B. `[-CH_2-overset(CN)overset(|)CH-]_n`
C. `[-CH_2-overset(CH_3)overset(|)CH-overset(CN)overset(|)CH-]_n`
D. `[-CH_2-overset(CH_3)overset(|)CH-]_n`
