mental ability

. A vagabond runs out of cigarettes. He searches for the stubs, having learnt that 7 stubs can make a new
cigarette, good enough to be smoked, he bathers 49 stubs, If has smokes 1 cigarette every three – quarters
of an hour, how long will his supply last ?
(A) 5.25 hr (B) 6 hr (C) 4.5 hr (D) 3 hr