[单选题]
An object is 4.1 cm tall, and 10.3 fs5p7 2v+ibye tw )-ebcm frow *y2tzc;ao v0)m4 yzum a converging lens. The image is virtual anda0zyv2y;cu 4 *zmot) w 6.2 cm tall. What is the focal length of the lens?
A. $6.8 \; cm$
B. $10 \; cm$
C. $16 \; cm$
D. $30 \; cm$