Answer:
The appropriate null hypothesis is 
The appropriate alternate hypothesis is 
Step-by-step explanation:
At the null hypothesis, we test if the mean area is the advertised area of 1250 square feet, that is:

A tenant group thinks that the apartments are smaller than advertised.
Smaller, thus, at the alternate hypothesis, we test if the mean area is less than the advertised area of 1250 square feet, that is:
