let me know the correct answers

The given sentence

  1. Certain factors are not given due consideration in your essay. (account)

This or similar meaning should be expressed using the word “account”, but not changing the form of the word given

The answers

  1. You fail to take certain factors into account in your essay.
  2. You fail to take account of certain factors in your essay.
  3. You fail in taking into account certain factors in your essay.

Could the right answer be

  1. You’ve failed in taking into account certain factors in your essay.

Which of these sentences are correct?
Anyway, why the simple present tense was used in #2 and #3, and not the present perfect tense?

Thanks

#2 and #3 are OK. “fail(ed) in taking into account” isn’t right.

The present tense makes sense because the essay exists now. “You’ve failed to take…” would also be OK, and in practice there is not a huge difference in meaning.

Dozy,
“You failed to take into account certain factors in your essay.”
Is this sentence correct?

Yes, that would also be OK. Fairly obviously, that one has more of a past tense feel.