Quiz: Residual Graph

An edge $(u, v)$ has capacity $10$ and carries $7$ units of flow. In the residual graph, what edges exist between $u$ and $v$?

1. A.$(u, v)$ with capacity $3$, and $(v, u)$ with capacity $7$
2. B.Only $(u, v)$ with residual capacity $10$
3. C.Only $(v, u)$ with residual capacity $7$
4. D.$(u, v)$ with capacity $7$, and $(v, u)$ with capacity $3$