Answer:
I would say C. Show the product in use in the advertisement.
Explanation The point of advertisement is that people immediately know if they want to have/buy the products advertised. With showing the product in use, you achieve exactly this. If person likes, what he sees, he buys the product.
On the other hand, if a person only sees random simple images, he may see pictures of not the product itself or the purpose for what it can be used. So he doesn't know, if he needs or wants the product.