Option A is incorrect: The passage nowhere specifies or even dwells upon the cost of generation of energy from municipal solid waste.

Option B is incorrect: The passage does outrightly state that “The biodegradable component of India's municipal solid waste is a little over 50 per cent, and biomethanation offers a major solution for processing this.” However, ‘major solution’ cannot be equated with ‘most ideal way’ in the strict sense. Further, the question is asking us to suggest the crux of the passage. The fact about bio methanation offering a major solution is a solution to the crux of the passage, which is about the issue of the rarity of segregation of municipal waste at source and achieving waste-to-energy amidst such a challenging scenario.

Option C is correct: The passage begins with laying the central theme that “In India, the segregation of municipal waste at source is rare.” Further, it goes on to say, “Where does waste-to-energy fit into all this ? Ideally, it fits in the chain after segregation (between wet waste and rest), collection, recycling, and before getting to the landfill.” This line lays the sequential chain of waste processing, which can further be re-aligned to generate energy. Hence from these lines, it is clear that the segregation of municipal solid waste is the first step in ensuring the success of waste-to-energy plants.

Option D is incorrect: The passage clearly refutes this by mentioning that “The biodegradable component of India's municipal solid waste is a little over 50 per cent, and biomethanation offers a major solution for processing this.”