In the given sentence the focus needs to be on the verb ‘trust’. The preposition ‘in’ is commonly used to speak about a state, condition or abstract concept. In addition to this, the phrasal verb ‘trust in’ means to have a strong belief in someone or something. God here is a large entity in which the person has faith. Thus option A is correct. On the other hand, the other prepositions are not added to the verb ‘trust’ to form a phrasal verb, because the other prepositions will change the meaning of the sentence. To trust ‘for’ God would mean that a person trusts something else to satisfy God. While ‘with’ suggests that the person and God trust some other thing/person. On the other hand ‘to’ is grammatically irrelevant here. Thus options B, C, and D are incorrect.