When whiskey first emerges from a still, and before it has been aged in oak with an extremely high alcohol content, it would be about 185 proof, which is strong enough to fuel an internal combustion engine.

a.oak with an extremely high alcohol content, it would be about 185 proof, which is strong enough to fuel an internal combustion engine
b.oak with an alcohol content that would be about 185 proof, it is strong enough to fuel an internal combustion engine
c.oak, it has an alcohol content of about 185 proof, which is strong enough to fuel an internal combustion engine
d.oak, if it were used to fuel an internal combustion engine, it would have an alcohol content of about 185 proof
e.oak, it has an alcohol content of about 185 proof, which would be as strong as that of an internal combustion engine

OA is C

I would love an expert to give a professional approach to solve this question. I believe parallelism comes into play here! OPtion D looks correct too