In little more than a decade, Argentina has become the world’s leading exporter of honey, with nearly 90,000 tons a year sold to foreign markets, almost half of which going to the United States.

(A) with nearly 90,000 tons a year sold to foreign markets, almost half of which going
(B) with the sale of nearly 90,000 tons a year to foreign markets, and almost half of it that goes
(C) with the sale to foreign markets of nearly 90,000 tons a year, with almost half of it going
(D) selling nearly 90,000 tons a year to foreign markets, and almost half of it goes
(E) selling nearly 90,000 tons a year to foreign markets, with almost half going

The original sentence "In little more than a decade, Argentina has become the world’s leading exporter of honey, with nearly 90,000 tons a year sold to foreign markets, almost half of which going to the United States," has a slightly strange structure. In the section "with nearly 90,000 tons a year sold to foreign markets, almost half of which going to the United States" we can notice the lack of parallelism.

Both sentences that comprise the said section contain a participle. The first one has a past participle, sold, while the second one has a present participle, going. The best thing to do would be to choose one of the two types of participle to make the sentences more uniform, providing parallelism. That is precisely what letter E does. It uses the present participle for both sentences, selling and going.

Thus,

In little more than a decade, Argentina has become the world’s leading exporter of honey, selling nearly 90,000 tons a year to foreign markets, with almost half going to the United States.