In the NaBH4 reduction of camphor:
a. The NaBH4 reduced the carbonyl group by adding a proton (H+) to the carbonyl carbon.
b. The NaBH4 reduced the carbonyl group by adding a hydrogen atom (H) to the carbonyl carbon.
c. The NaBH4 reduced the carbonyl group by adding hydride (H:-) to the carbonyl carbon.
d. The NaBH4 provided a catalytic surface for the one step addition of a hydrogen molecule (H2) across the carbonyl double bond.
e. The NaBH4 reacted with ethanol to give (CH3CH2OH2)- which was the actual reducing agent that attacked camphor.
Answer: c. The NaBH4 reduced the carbonyl group by adding hydride (H:-) to the carbonyl carbon.