Correct Answer: A
Explanation:
When constructing sentences unnecessary shifts in verb tenses should be avoided. Choice A is best because all three verbs in the sentence indicate that the action occurred in the past (had been covering, became, and was called). In choice B, there is a shift to the present (becomes). Choice C begins in the present (is covering, becomes), then shifts to the past (called). Choice D makes two tense shifts, and choice E shifts once, from present to past tense.