Time and work question

A work is done by 30 workers, not all of them have same capacity to work. Everyday exactly 2 workers working, do the work, with no pair of workers work in together twice. Even after all possible pair have work once , all the workers together works for two more days to finish the work. Find the no. of days in which all the workers together will finish the work???? Options:- A- 22 days B- 20 days C- 24 days D- 30 days E- 32 days F- 31 days