Seema works at a rate such that she can finish a work in 28 h, bur she works at this rate for 7 h only. After that, she works at a rate such that she can finish the remaining work in 16 h. If Seema is to finish this work at a stretch, how many hours (total) will she take to finish this work?

A

21

B

18

C

14

D

19