If We Are Interested in Testing Whether the Mean of Population

If we are interested in testing whether the mean of population 1 is significantly smaller than the mean of population 2, the

A) null hypothesis should state $\mu$ ₁ - $\mu$ ₂ $\lt$ 0
B) null hypothesis should state $\mu$ ₁ - $\mu$ ₂ $\le$ 0
C) alternative hypothesis should state $\mu$ ₁ - $\mu$ ₂ $\lt$ 0
D) alternative hypothesis should state $\mu$ ₁ - $\mu$ ₂ $\gt$ 0