When Are the Two-Sample T Procedures Accurate

When are the two-Sample t procedures accurate?

A) When both populations are Normal and both sample sizes n₁ and n₂ are 5 or larger
B) When at least one of the populations is Normal and both sample sizes n₁ and n₂ are 5 or larger
C) When both populations are Normal and only one of sample sizes n₁ and n₂ is 5 or larger
D) When both populations are Normal and the combined sample size n₁ + n₂ is 5 or larger