Quote:
Source: Ready4GMAT
The rising cost of fuel has become a political focus and perhaps even threatening the future of some government subsidies given the struggling economy.
A) and perhaps even threatening
B) and may even threaten
C) and could have been a threat to
D) as well as possibly threatening
E) and could maybe threaten
A is a blatant fragment with no verb to match has become. B is acceptable. C changes the meaning and E is colloquial and redundant with the use of could and maybe.
However, D has to be clarified. The use of the ing form after as well is the accepted idiomatic usage. As well as possibly threatening means as well as possibly threatens. Since as well as is not a fanboy conjunction, there is no need to worry about parallelism.
Quote:
VERBS AFTER AS WELL AS COME IN –ING FORM (
https://site.uit.no/english/grammar/aswellas/)
When we put a verb after as well as, we use the -ing form of the verb. (This might sound really strange to a non-native speaker, but the grammar books agree on this.)
Running is healthy as well as making you feel good.
He broke the window, as well as destroying the wall.
She draws as well as designing clothes.
Why is then D not the choice? The intruding adverb 'possibly' is the spoilsport. Being an adverb, it cannot modify a verb+ing form, be it a present participle or a gerund. The splitting of the prepositional phrase as well as threatening is also a style error.
Therefore, B is the correct choice.