There are $20$ cards numbered from $1$ to $20$, respectively. What is the probability of taking out a card with a prime number? 
选项为:A:$\dfrac{3}{10}$  B:$\dfrac{7}{20}$  C:$\dfrac{2}{5}$  D:$\dfrac{9}{20}$  请回答其中一个选项.