The correct option is B 61.5 g
The molar masses of cyclohexanol and cyclohexene are 100 g/mol and 82 g/mol respectively. When 100 g of cyclohexanol are dehydrated, 82 g of cyclohexene are obtained. This is assuming 100% yield. But the dehydration yield is 75%.
Hence, when 100 g of cyclohexanol are dehydrated, the yield of cyclohexene is 82×75100=61.5 g.