So why is "the" mandatory here? I also put "you drink tea in Azerbaijan" and was marked wrong. Considering the rule that if the object (çay) is not immediately preceding the verb, it has to be in the accusative no matter what, I think both versions (with and without "the") could be acceptable. One just has to invent the appropriate context to justify it. Am I mistaken? Thanks.
My understanding is that it is kind of the other way round: If the direct object is not a definite object ([some] tea), then common word order demands that it will go to the position immediately preceding the verb and it does not take the accusative suffix. If the direct object is a definite object (the tea), its place is at the beginning of the phrase (away from the verb which usually gets the last position) and takes the acccusative suffix.