Find the Indicated Sum or Difference $$- a - 2 a + ( - 2 ) a$$

Multiple Choice

Find the indicated sum or difference. $$- a - 2 a + ( - 2 ) a$$

A) $- 4 a$
B) $5 a$
C) $- 8 a$
D) $- 5 a$
E) $- 3 a ^ { 3 }$