In the sentence of the text “Although commercial refueling ...

D) al·though
 (ôl-thō′)
conj.
1. Regardless of the fact that; even though: Although the room is big, it won't hold all that furniture.
2. But; however: He says he has a dog, although I've never seen it.
[Middle English : al, all; see all + though, though; see though.]
Usage Note: As conjunctions, although and though are generally interchangeable: Although (or though) she smiled, she was angry. Although usually occurs at the beginning of its clause (as in the preceding example), whereas though may occur elsewhere and is the more common term when used to link words or phrases, as in wiser though poorer. In certain constructions, however, only though is acceptable. When though introduces only a part of a clause rather than a whole clause, although is not possible: Most people in attendance applauded loudly after the performance, though (not although) not everyone. Another construction that requires though is the following: Fond though (not although) I am of sports, I'd rather not sit through another basketball game.

Na sentença do texto "Apesar das estações de reabastecimento comerciais serem necessárias para apoiar uma frota de veículos movidos a gás natural, a casa de reabastecimento pode ser a bala mágica que faz com que os veículos práticos" (linhas 76-79), a palavra implica, embora fatos que são

   a) simultâneo

   b) sequencial

   c) alternativa

   d) opondo

   e) proporcional

Although é a nossa conjunção adversativa mais conhecida como mas, porém, entretanto... 

Gabarito correto é "D"

Acredito que although esteja mais próximo das conjunções concessivas, como apesar de, embora etc. 

D)

Apesar, embora, as estações de reabastecimento comercial...