In a box, there are $10$ balls of which $4$ are red, $3$ are black and $3$ are white. What is the probability of picking up $3$ balls randomly such that there are $2$ red balls and $1$ balck ball? 
选项为:A:$\frac12$  B:$\frac13$  C:$\frac1{12}$  D:$\dfrac{3}{20}$  请回答其中一个选项.