AMC 12 2007b Problem 6

Triangle $ABC$ has side lengths $AB = 5$, $BC = 6$, and $AC = 7$. Two bugs start simultaneously from $A$ and crawl along the sides of the triangle in opposite directions at the same speed. They meet at point $D$. What is $BD$?

$\mathrm {(A)} 1 \mathrm {(B)} 2 \mathrm {(C)} 3 \mathrm {(D)} 4 \mathrm {(E)} 5$