158) Anne-Marie’s business goal is to generate online sales of her handmade purses. Her AdWords costs are $100 per week and she wants to know if her advertising investment is paying off. What additional information do you need in order to calculate her return on investment (ROI)?

A)  Number of clicks on her ads and costs to produce her purses

B)  How many times her ads have been viewed and clicked on

C)  Number of clicks on her ads and revenue they generated

D)  Costs to produce her purses and revenue generated from her ads