Collect Like Terms $-13 b^{7}+8 b^{6}-2 b^{5}+4 b^{7}-3 b^{6}$ A) $-216 b$

Multiple Choice

Collect like terms.
- $-13 b^{7}+8 b^{6}-2 b^{5}+4 b^{7}-3 b^{6}$

A) $-216 b$
B) Can't be simplified
C) $-12 b^{18}$
D) $-9 b^{7}+5 b^{6}-2 b^{5}$