Why does pumping more air into a basketball increse the pressure inside the ball?

Think of it as a balloon when you pump air into it it grows bigger but, if you put too much air into it what happens it pops because the pressure was too much for the balloon to withhold. That's the same with a basketball when you pump air into it the pressure pushing on the material increases.    

Idid the calculation and i get 875,000,000 which can be written as 8.75 x 10^6?

The answer should be c.