Answer: Exponential
Step-by-step explanation:
The first figure has 2 blocks.
The second figure has 4 blocks.
The third figure has 8 blocks
The pattern 2,4,8,... follows the rule "double the current value to get the next one". Because we have this going on, we have an exponential pattern here.
A linear pattern would be something like 2,4,6,8,10,... showing that we add on 2 each time, rather than multiply by 2 each time. So as you can guess, or already know, exponential patterns grow much quicker compared to linear ones.