Nothing's missing: the normal to a point on the graph of a function is a straightline through that point which perpendicular to the tangent to the function on that point, so you must:
1) derivate your function
2) find what the slope of a NORMAL to any point of the graph is
3) make this slope equal to the given line's slope (so that they'll be parallel)
4) solve and find out what x is, and then substitute in the function and find out what the y-coordinate is.
The answer is (D)