I have Economics class this semester and I need help with this question. I have trouble with graphs in this class.

I have Economics class this semester and I need help with this question. I have trouble with graphs in this class.

Can someone steer me in the right direction on how to answer this?

8. What happens along the average total cost curve as:

a) Marginal product is increasing?

b) Marginal cost is decreasing?

c) Average variable costs are decreasing?

d) Total product increases at a decreasing rate?