Yohan had 10 white socks, 10 red socks and 10 black socks in his drawer. How  many socks at most, must Yohan take from his drawer without looking, till he gets a pair of white socks? 
选项为:A:$$11$$  B:$$15$$  C:$$21$$  D:$$22$$  E:$$23$$  请回答其中一个选项.