likely be likely to The others don't make any sense.

A is correct because the others don't make sense

you need a adverb there to modify 'win' possible and probable are adjectives, so those are no good. you would have to change them to adverbs to use them, but you would still have to change the sentence some: - he will possibly win.....and....he will probably win. CORRECT however these are wrong V - he is possibly to win....and....he is probably to win. INCORRECT 'perhaps' is an adverb. I don't know why it can't go there; I just know it doesn't sound right. Perhaps, it is because 'perhaps' usually goes at the beginning of a clause: - Perhaps it will rain. - Perhaps we were late. so you could say.... - Perhaps he will win. or even.... - he will win, perhaps. No that is not right because you can say: - He is perhaps the best chef I have met. Sorry I don't know why you can't put perhaps in that spot. Can someone who actually understands Grammar help?