Is this pattern linear, exponential, or quadratic?

Question

1. Here is a pattern of squares. S represents the number of small squares in the pattern as a function of n, the step number.

1. Which expression could define S?
2. 3n
3. 2n
4. n2+1
5. n2+n

Answer 1

best guess I can make is without seeing a diagram is a) 3n, a linear relation

if there are squares that increase by 1 each step

then they're 1, 2, 3, 4, ....

add them up and they = 3n for 1 step 1+2=3

for n=2, 1+2+3= 6 = 3n = 3(2) = 6