In a sequence of numbers, a4=12, a5=14, a6=16, a7=18, and a8=20.

Which equation can be used to find the nth term of the sequence, an?

a) an=2n+4

b) an=2n+12

c) an=3n

d) an=3n+12

I'm pretty sure it's a, but I just wanna check if I did the work right!