Abe has $1$ green and $1$ red jelly bean in his hand. Bob has $1$ green and $2$ yellow jelly beans in his hand. Each randomly picks a jelly bean to show to the other. What is the probability that the colours match? ． 
选项为:A:$\dfrac{1}{2}$  B:$\dfrac{1}{3}$  C:$\dfrac{3}{4}$  D:$\dfrac{1}{6}$  E:$\frac{1}{9}$  请回答其中一个选项.