Which of the Following Graphs Are Symmetric About the Y-Axis $y = x ^ { 7 } - x ^ { 6 } + 18$

Multiple Choice

Which of the following graphs are symmetric about the y-axis?

A) $y = x ^ { 7 } - x ^ { 6 } + 18$
B) $y = x ^ { 7 } - x ^ { 12 } + 18$
C) $y = x ^ { 9 } - x ^ { 7 } + 18$
D) $y = x ^ { 12 } - x ^ { 6 } + 18$
E) $y = x ^ { 9 } + x ^ { 7 } + 18$