Availability of energy resources

Steps:

• Define "yes at all times" as baseload energy available continuously without weather dependence.
• Classify biofuels as dispatchable since biomass can be harvested, processed, and stored for steady supply.
• Evaluate nuclear for operational limits like refueling shutdowns every 18-24 months.
• Confirm wind and solar as intermittent due to variable natural conditions.

Why A is correct:

• Biofuels are produced from renewable biomass that allows on-demand generation and storage, ensuring constant availability per energy dispatchability definitions.

Why the others are wrong:

• B: Nuclear requires scheduled outages for fuel replacement and maintenance, interrupting continuous supply.
• C: Wind energy is intermittent, relying on inconsistent wind speeds, so it cannot be available at all times.
• D: Solar energy is intermittent, limited by daylight hours and cloud cover, preventing all-times availability.

Final answer: A