The correct option is C He was a man rich in intelligence.
In the given sentence, the adjective 'rich' here modifies the noun 'man'. That is correct, however, the following clause "in intelligence" is grammatically incorrect in the context of the sentence, it needs to be changed and the adjective should precede the noun 'intelligence' as it makes the sentence sound complete in meaning. Hence option D is incorrect. Option C is correct because the adjective 'rich' modifies the noun 'intelligence', where 'rich' here is followed by 'in' because 'intelligence' is an abstract noun and a preposition links the adjective to the noun. When we omit 'in' from the phrase, and place it before 'rich intelligence', the statement is grammatically incorrect, and hence option A is wrong. Option B has a jumble of phrases that don't go together, 'intelligence' is a noun which is being used as an adjective, followed by the preposition 'in' which attributes the physical meaning of intelligence in a rich man, which is grammatically incorrect, hence option B is wrong.