Which of the following sentences advocates an idea in a positive way?

A "I can't see anyone buying the product at that price."
B "The unit is way overpriced."
C "Customers can get a better deal anywhere else."
D "We can corner the market if we discount the selling price just 5%."

I believe the answer to this is D because it seems that they would be offering an alternative that could be beneficial to them?

I agree. It's the only positive statement.

You are correct! Sentence D "We can corner the market if we discount the selling price just 5%" advocates an idea in a positive way. In this sentence, the speaker is proposing a solution or strategy to achieve a goal, which is to corner the market. By offering a discount of just 5% on the selling price, they believe it will be beneficial and help them achieve their objective. This sentence presents a positive outlook and a possible opportunity for success.