a) part a) is before.. so irrelevant a) part b) is guess.. so no better than anything I have said b) incorrect.. as burning a fuel to directly produce mechanic

a) part a) is before.. so irrelevant a) part b) is guess.. so no better than anything I have said b) incorrect.. as burning a fuel to directly produce mechanical energy that is used as mechanical energy is more efficient than.. burning fuel to produce mechanical energy to drive a generator to make electricity, to store it, to retrieve it, and then drive an electrical motor, to produce mechanical energy to use.