OG详解-OG1 文法 Q1

Choice A is the best answer. The convention being tested is pronoun-antecedent agreement. The plural pronoun “they” agrees in number with the plural antecedent “customers.”
Choice B is incorrect because the singular pronoun “one” doesn’t agree in number with the plural antecedent “customers.” Choice C is incorrect because the second person pronoun “you” isn’t conventional as a substitute for “customers.”It suggests that the audience (“you”) is the customer. Choice D is incorrect because the singular pronoun “it” doesn’t agree in number with the plural antecedent “customers.”