Concept:The sentence is a third conditional that describes a past situation that did not actually happen.Explanation:"Had it not rained" means "If it had not rained."This refers to an imaginary past condition.The result clause, "I would have visited you," shows what would have happened if that condition were true.Because the condition is contrary to reality, it means that it did rain.Therefore, the speaker did not visit you.The most appropriate interpretation is the one that links the rain to the missed visit.Answer:C. It rained so I did not visit you.