Correct Option (D)
All three statements represent present constraints in using biomass as fuel for power generation, as directly supported by the provided passage.
- Statement 1: The passage explicitly states, "The biggest challenge in using biomass residues is a long-term reliable supply delivered to the power plant at reasonable costs; the key problems are logistical constraints and the costs of fuel collection." This indicates a lack of sustainable and economically viable supply.
- Statement 2: The passage mentions, "Energy crops, if not managed properly, compete with food production and may have undesirable impacts on food prices." This highlights the competition with food production as a significant constraint.
- Statement 3: The passage notes, "Some liquid biofuels such as corn-based ethanol, mainly for transport, may aggravate rather than ameliorate carbon emissions on a life-cycle basis." This indicates that bio-energy, in certain forms, may not always result in low carbon emissions when considering its entire life cycle.
Incorrect Options:
Options (A), (B), and (C) are incorrect because they selectively identify only one or two of the constraints. The passage clearly identifies all three listed points as present constraints in the use of biomass as fuel for power generation.