when to use a gerund and an infinitive?

[Maggie]

Hi,guys

I have done one English question. I want to know wheather my answer is okay.

[Conchita]

Sue needs money -- it's not a purpose, but a fact. What does she need the money for? To buy a new computer -- that's the purpose.

(A) Needing is the correct option and has the sense of 'Since she needed'.

[Haihao]

Dona Conchita's explanation is more than convincing to me. If we chose (D), then the sentence could be reworded as:

Sue cashed a check to need some money to buy a new computer.

This would be illogical because the purpose of her cashing a check is not to need some money but to buy a new computer, which is also the purpose of needing some money itself.

[Maggie]

Thanks so much. Your explanations make sense to me completely.
Greetings!

Maggie^^
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