Find out whether there is any grammatical error in below sentence. They have been / very close friends / until they quarrelled.

The correct answer is: D. No error

The sentence “They have been very close friends until they quarrelled” is grammatically correct. The word “until” is used to introduce a time when something happens or stops happening. In this case, it is used to introduce the time when the friends stopped being close. The sentence is clear and easy to understand.

The other options are incorrect because they contain grammatical errors. Option A, “They have been,” is missing a verb. Option B, “very close