[单选题]
A box is sliding down an inca qw0/s,k-:rfnp2 y x( ,bfhopline at zvw+(t gz 8hp0a 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. $\frac{16}{cos \theta}$