Which situation can be represented by this inequality? 72 < 9r + 12

A

Rory has 12 rocks in his collection. He will collect 9 new rocks every month. Rory collects rocks for r months. For what values of r will Rory have at most 72 rocks?

B

Rory has 9 rocks in his collection. He will collect 12 new rocks every month. Rory collects rocks for r months. For what values of r will Rory have at most 72 rocks?

C

Rory has 12 rocks in his collection. He will collect 9 new rocks every month. Rory collects rocks for r months. For what values of r will Rory have at least 72 rocks?

D

Rory has 9 rocks in his collection. He will collect 12 new rocks every month. Rory collects rocks for r months. For what values of r will Rory have at least 72 rocks?