Please choose the correct option and give reasons also.
The correct answer is option (b) most of what.
This is because in the given sentence, we need to use the superlative degree and 'most' is the superlative form of many and much. It indicates the greatest in number
Regarding option (c), the given sentence is generic and does not talk of anything specific while 'this' is used for something specific. So, option (c) also becomes incorrect.