Determine the Degree of the Polynomial $- a + 8 a ^ { 3 } - 4 a ^ { 7 } + 2 a ^ { 2 }$

Multiple Choice

Determine the degree of the polynomial.
- $- a + 8 a ^ { 3 } - 4 a ^ { 7 } + 2 a ^ { 2 }$

A) 7
B) 4
C) 13
D) 12