I think its C

If n is the number of pieces done by each clerk in 1 hour, then it can be given by 20 ≤ n ≤ 30.

For (1) what six clerks can do in an hour is 120 ≤ 6 n ≤ 180. If each of the 70 people in line has at least one of the present to be wrapped by one of the six clerks at the counter, then a minimum of 70 presents can definitely be wrapped within an hour, but in case of a multiple number of gifts in a multiple number of hands in the queue, we become clue-less. Say no to A.

For (2) the minimum possible number of presents will be 140 in this case, with higher possibilities, we are clue-less. If 9 clerks are required to get it done in an hour, it means the total number of presents must be between 180 and 270, both inclusive.

I don’t know what we are doing here. We are answering to “will all of their presents be wrapped in one hour?” How many presents are really there in total? Statement (2) probably answers it. Not really, it simply gives a case (see it reads the word ‘if’) How many clerks are really available with us? Statement (1) probably answers it. Yes it does, but it answers only a part of what whole is required to answer it. We are vacillating between iffy and butte with the correct number of presents required being wrapped-up by the 6 available clerks.

Let’s too wrap it up now with E. Not correctly worded for C to be the OA, IMO.