If We Are Interested in Testing a Null Hypothesis That $\mu$

If we are interested in testing a null hypothesis that the mean of Population 1 is smaller than the mean of Population 2, the

A) null hypothesis should state $\mu$ ₁ - $\mu$ ₂ < 0
B) null hypothesis should state $\mu$ ₁ - $\mu$ ₂ > 0
C) alternative hypothesis should state $\mu$ ₁ - $\mu$ ₂ $\ge$ 0
D) alternative hypothesis should state $\mu$ ₁ - $\mu$ ₂ < 0
E) none of the above