The correct answer is:<em> "menos" ("less"). </em>
Explanation:
The phrase says in English: <em>"My favorite dress is cheaper than yours. I'm going to pay ___"</em>, which is referring to two dresses: the favorite one and the other one. A correct inference of this would be that if <em>the favorite it's cheaper than the other one</em>, therefore you would pay LESS for the favorite than for the other one, so the <em>correct answer is the word "</em><em>less</em><em>", which in Spanish is "menos". </em>
This rule is a specific kind of rule and it’s used in all science classes and grades including middle school but it’s basically like saying soft or softer or maybe softest
