[单选题]
A box is sliding dow ode(ycr).u9o:c(q*y9 x0u (xgeavasnvpw; yae)-y1 :zccc3x an incline at a constant speed of $2\,ms^{−1}$. The angle of the incline is $\theta$.
The magnitude of the total of the opposing forces is $16\,N$. What is the force of gravity acting on the box?
A. $\frac{8}{sin \theta}$
B. $\frac{16}{sin \theta}$
C. $\frac{8}{cos \theta}$
D. $\frac{16}{cos \theta}$
