[单选题]
An object is placed 40 cm +,qli,op s 3mbin front of a 20 cm focal length lg:mp;.hai1 9fms w w*fp zi+-converging lens. How-a :*.;i+sfwwfpgmh 9pl1miz far is the image of this object from the lens?
A. $40 \; cm$
B. $20 \; cm$
C. $13 \; cm$
D. none of the given answers
