The correct answer is D.
As you can see, the exponential function grows by doubling the previous output with each increment of the input: start with 1, you double it to get 2, then you double it to get 4, 8 and so on.
On the other hand, the linear function adds 7 with each step. This means that the exponential function will eventually reach and pass the linear one, and will definitely be grater from that point on. In fact, if we continue the table, we get

and you can see how the exponential growth is much faster than the linear one.
6.299 or 6.3 depending on how it wants you to round
16cm / 2.54 cm per in = 6.3 inches
Yes, 90 is 1/10 of 900
Because
90 = 1/10 x 900
90 = 90
1 1/2 or 3/2 because there is 4 more than 8 which is a half.