C because if the line Q is 1,5 and 1,8, it would have to be a vertical line, as the X axis doesn’t change. As i know, a vertical line always has a slope of 0, and a horizontal line (which the x-axis is) always has an undefined slope.
Given:

To find:
The function
.
Solution:
we have,

Put g(x)=y.

Interchange x and y.

Isolate y.



Substitute
.



Therefore, the correct option is (3).