Question

The greatest goal in advertising is to convince us

"wants" are unnecessary.
the firm has the best price.
a particular product is a "need."
the product is the same as other firm's products.

Answer 1

c. a particular product is a "need"

Step-by-step explanation:

Answer 2

The greatest goal in advertising is to convince people that they actually need a particular product.

The alternatives: the first and the last would actually make people not buy the products. The second option is also a goal, but a minor one: unless people want to buy something, the prize is irrelevant.