Which expression is equivalent to (3+7b-b2)-(10b2+18-8b)?

Which expression is equivalent to (3+7b-b2)-(10b2+18-8b)?

-11b2+15b-15

11b2+15b+21

-9b2-b+21

9b2-b-15

The correct expression equivalent to (3+7b-b2)-(10b2+18-8b) is -9b2 - b + 21

that is incorrect

I apologize for the mistake. Please allow me to correct my response.

The correct expression equivalent to (3+7b-b2)-(10b2+18-8b) is 11b2 + 15b + 21.