A ≡ number is a multiple of 64
B ≡ number is a multiple of 8
C ≡ number is a multiple of 2
Using (A → B) ∩ (B → C) → (A → C), the direct conclusion is:
If a number is a multiple of 64, then it is a multiple of 2.
Using (A → C) → (~C → ~A), the contrapositive of the direct conclusion is:
If a number is not a multiple of 2, then the number is not a multiple of 64.
Thus, both d and c are valid, syllogistic conclusions.