Sentence 5: It is estimated that there were over four million tractor-trailer combinations on the roads, delivering three out of every four tons of goods.
Which of the following options would CORRECT sentence 5?

In order to correct sentence 5, the past tense verb \u201Cwere\u201D should be changed to the present tense verb \u201Care.\u201D The beginning of the sentence is written in the present tense (\u201CIt is ...\u201D); therefore, the remainder of the sentence should also be written in the present tense.