[单选题]
An object of mass $m$ with a speed of $3.0\,m\;s^{-1}$ collides horizontally with a stationary box of mass $2\,m$. After the collision, the object and the box move together.
The friction acting on the box and the object is $6.0\,N$.
Which expression gives total distance travelled by the combined objects before coming to rest after the collision?
A. $\frac{m}{16}$
B. $\frac{m}{12}$
C. $\frac{m}{8}$
D. $\frac{m}{4}$
