The farmer has a fish, a cat, and a dog. He wants to take them cross the river by boat, and he can only take one animal each time. When the farmer is away, the cat cannot be put with the fish or the dog, or they will fight. The boat makes one trip from one side of the river to the other side, so it takes~\uline{~~~~~~~~~~}~trips in total to carry all the animals and farmers cross the river. 
选项为:A:$$3$$  B:$$4$$  C:$$5$$  D:$$6$$  E:$$7$$  请回答其中一个选项.