Add the Polynomials $6 z ^ { 4 } + 9 z + 10 \text { and } - 6 z ^ { 4 } - 7 z + 10$

Multiple Choice

Add the polynomials. $6 z ^ { 4 } + 9 z + 10 \text { and } - 6 z ^ { 4 } - 7 z + 10$

A) $2 z - 20$
B) $2 z + 20$
C) $12 z ^ { 4 } + 2 z + 20$