Which function is symmetric with respect to the y axis?
a. y=-x^5
b. y=3x^6
c. y=2x^7
d. y=-2x^3

This is a test of even or odd function
if it is even it is symmetric with respect to y axis
means if we replace x with -x, we should get the same thing

in an even function, f(x)=f(-x)
so

a. if we replace x with -x we get y=x^5, not the same function
b. if we replace x with -x, we get 3x^6, same thing
c. replace to get -2x^7
d. replace and get 2x^3

B is answer
notice that the even powers canclel out the positive so normally even functions have even degrees

B is answer

Yes you are correct