Punctuation in IELTS Listening

by Aiana
(Kazakhstan)

Can I write answers using commas?

The speaker on the tape was talking about vitamins, their functions, which products we can get them from. When talking about vitamin C she said:

We need 30 mg a day, and can only really get this amount from eating plenty of citrus fruit and fresh vegetables.

(Her exact words. If you are wondered how I managed to memorize them: I was doing a practice listening and I just pasted the sentence from a transcript)

I could write no more than 3 words, and in a column where to get it, I wrote: citrus fruits, vegetables.

In answer key, the correct answer was: fruits and vegetables.

So my questions is: can I write answers using commas or it will be considered as incorrect?