A: Cation at C1. α-carbons are Methyl (3H), C2 (1H), C6 (2H). Total = 6.
B: Cation at C1. α-carbons are Methyl (3H), C2 (2H), C6 (2H). Total = 7.
C: Cation at C1. α-carbons are Methyl (3H), C2 (1H), C6 (2H). Total = 6.
D: Cation at C1. α-carbons are Ethyl group's CH2 (2H), C2 (1H), C6 (2H). Total = 5.
A and C both have 6 α-hydrogens, thus they have the same number of hyperconjugation structures.
