There are $12$ black balls, $27$ red balls, and $11$ blue balls in an opaque box. The balls are the same except for their colors. Bob adds several red balls in the box and mixes the balls. Now, if the probability of taking out a black ball is $\frac15$, how many red balls does Bob add? 
选项为:A:$$5$$  B:$$10$$  C:$$15$$  D:$$20$$  E:$$25$$  请回答其中一个选项.