Discrete Math Functions help?

I am working a discrete math homework problem involving functions that I am having troubles with. The question I am working on currently is this:

Let A = {1,2,3,4} and B = {x,y,z}

a) List five functions from A to B.

b) How many functions f: A -> B are there?

c) How many functions f: A -> B are one-to-one?

d) How many functions g: B -> A are there?

For part A, is it talking about doing something like, A -> B, A -> A, B ->A, B -> B, and not sure what the fifth function would be. But, would that be the correct way to go abouts it? If it's not, then I am not sure what the question is talking about