At Clover View Junior High, one half of the students go home on the school bus.  One fourth go home by automobile.  One tenth go home on their bicycles.  The rest walk home.  What fractional part of the students walk home?
$\text{(A)}\ \dfrac{1}{16} \qquad \text{(B)}\ \dfrac{3}{20} \qquad \text{(C)}\ \dfrac{1}{3} \qquad \text{(D)}\ \dfrac{17}{20} \qquad \text{(E)}\ \dfrac{9}{10}$
The students who walk home are
$1 - \frac{1}{2} - \frac{1}{4} - \frac{1}{10}$
$\frac{1}{2} - \frac{1}{4} - \frac{1}{10}$
$\frac{1}{4} - \frac{1}{10}$
$\frac{5}{20} - \frac{2}{20}$
$\frac{3}{20}$ of the entire student population.  Therefore, the answer is $\boxed{B}$.