[单选题]
A convex lens has a xf9h9 wfr 54xi:(hi)wpvcn y5focal lengt/xs xdujw(l5rsd2hh p* ;r 2g9h $f$. An object is placed between infinity and $2f$ from the lens on its axis. The image formed is located
A. at $2f$.
B. between $f$ and $2f$.
C. at $f$.
D. between the lens and $f$.
