parallel structure

[BTGmoderatorRO]

Tropical bats play important roles in the rain forest ecosystem, aiding in the dispersal of cashew, date, and fig seeds; pollinating banana, breadfruit, and mango trees; and indirectly help produce tequila by pollinating agave plants.

(a) pollinating banana, breadfruit, and mango trees; and indirectly help produce
(b) pollinating banana, breadfruit, and mango trees; and indirectly helping to produce
(c) pollinating banana, breadfruit, and mango trees; and they indirectly help to produce
(d) they pollinate banana, breadfruit, and mango trees; and indirectly help producing
(e) they pollinate banana, breadfruit, and mango trees: indirectly helping the producing of
OA is b
what approach can i use to get the correct answer here? can anyone help me out?
Thank you so much

[EconomistGMATTutor]

Hello!

When looking at questions for problems of parallelism, one easy way to find the right answer is to focus the actions/verbs and see if they all match. So for this question, I'll take out each of the action verbs in the list so you can see them without all the extra text in the way:

(a) pollinating / help
(b) pollinating / helping
(c) pollinating / help
(d) pollinate / producing
(e) pollinate / helping

B is the only answer that uses the same action verbs in both places; they are both -ing words. Since none of the other answers have matching action words, we know this one is the correct option.

I hope this helps! I'm available if you'd like any follow up.