Answer:
The correct answer is: "menos" ("less").
Explanation:
The phrase says in English: "My favorite dress is cheaper than yours. I'm going to pay ___", which is referring to two dresses: the favorite one and the other one. A correct inference of this would be that if the favorite it's cheaper than the other one, therefore you would pay LESS for the favorite than for the other one, so the correct answer is the word "less", which in Spanish is "menos".
