Sandra has a bag of $12$ counters.  $3$ of the counters are red.  $2$ of the counters are blue.  The rest of the counters are yellow.  Sandra takes at random a counter from the bag.  What is the probability that the counter is yellow? 
选项为:A:$\dfrac{5}{7}$  B:$\dfrac{7}{12}$  C:$\dfrac{3}{12}$  D:$\dfrac{2}{12}$  请回答其中一个选项.