$$42$$ children are lined up to go on an autumn trip,~ $$Y$$ is the $$22$$th from the front and $$M$$ is the~~$$22$$th from the back of the line. How many children are between $$Y$$ and $$X$$?  $$42$$个小朋友排成一队去秋游，从排头往后数，小$$Y$$是第$$22$$个，从排尾往前数，小$$M$$是第$$22$$个，小$$Y$$和小$$M$$中间有个人． 
选项为:A:$$0$$  B:$$1$$  C:$$2$$  D:$$3$$  E:$$4$$  请回答其中一个选项.