Answer:
Option four, 6b + 4r
Explanation:
So the two mini-type equations are joined together with a plus. Which means the parenthesis don't do anything in this particular equation. You simply add all of the same variables together. (r's go w/ r's, b's go w/ b's)
(2b + 3r) + (4b + r)
2b + 4b + 3r + r
6b + 4r
I hope that helps :)