Answer:
The correct answer is: Option C. Aquéllos.
Step-by-step explanation:
Although all of the options are valid demonstrative adjectives, the correct answer is the one with the ending that corresponds to the gender and number of the noun that the speaker is referring to.
In this case the speaker is talking about “pantalones” (pants or trousers) which in Spanish is always a plural and masculine noun. On the other hand, from the four demonstrative adjectives given as options, the only one that is properly used with plural masculine nouns is “aquellos”.
Note: The accent mark on the options C and D is no longer used in modern Spanish.