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 ) 3 hr
( B ) 5.25 hr
( C ) 4.5 hr
( D ) 6 hr
