It's competition because all you literally have to do is know the meaning of the words. Price means how much it'll cost, Demand means the desire of purchasers, Profit means how much money you made/make, and Competition literally means Rivalry.
Competition is the answer to this question. The reason being is because it is discussing rivalry. Profit is how much money one made. Price is how much something costs. Demand is how much an item is desired.
