Answer: B) Shift 3 units down
Recall that y = f(x) as both describe outputs of a function. The same applies for g(x) as well. Saying f(x)-3 means y-3. So we're subtracting 3 from the y coordinate of each point. A point like (1,5) moves to (1,2). Doing this to all points on f(x) will move the entire curve down 3 units.