Collect Like Terms $7 a^{9}-4 a^{9}+15 a^{8}+11 a^{9}-4 a^{8}$ A) $25 \mathrm{a}^{9}$

Multiple Choice

Collect like terms.
- $7 a^{9}-4 a^{9}+15 a^{8}+11 a^{9}-4 a^{8}$

A) $25 \mathrm{a}^{9}$
B) $14 \mathrm{a}^{9}+11 \mathrm{a}^{8}$
C) Can't be simplified
D) $25 \mathrm{a} ^{17}$