Classify Each Alkene in Vitamin D₃ Labeled I,II,III by the Number

Classify each alkene in vitamin D₃ labeled I,II,III by the number of carbon substituents bonded to the double bond.

A) I = Disubstituted; II = trisubstituted; III = trisubstituted
B) I = Monosubstituted; II = disubstituted; III = trisubstituted
C) I = Disubstituted; II = disubstituted; III = trisubstituted
D) I = Disubstituted; II = trisubstituted; III = disubstituted