is this A??? help please.

Answer:
A
Step-by-step explanation:
It obviously multiplies by 2 each time since all the slopes are 2, so we are looking at the right n base here.
a_{1} = 2
a_{2} = 4
a_{3} = 8
and so on...
Plug in 2 for n and see if we get 4.
a_{2} = 2a_{2-1}
a_{2} = 2a_{1}
4 = 4
Since 2 * 2 = 4
A is correct