Efficiency based on provided data

Steps:

• Identify efficiency as output energy divided by input energy, expressed as a percentage.
• Compare efficiencies from the data: hydroelectric (lowest %), nuclear (medium %), oil (highest %).
• Determine least efficient as the one with smallest percentage (hydroelectric).
• Determine most efficient as the one with largest percentage (oil).

Why C is correct:

• Matches data where hydroelectric has the lowest efficiency ratio and oil the highest, per energy conversion formula.

Why the others are wrong:

• A: Reverses order; nuclear is not most efficient.
• B: Nuclear is not least; oil not most per data.
• D: Hydroelectric is not most; oil is least per data.

Not enough information to confirm without visible data, but assuming stated correctness.

Final answer: C