[单选题]
A convex spherical mirror has a focal lengthb t,u drq(wlpd92b 83w of -20 cm. An obje:v0ocxgvf9w2 ct is placed 30 cm in front of the mirror on the mirror's axis. Where is thg0 :9ovv2xwcf e image located?
A. 12 cm in front of the mirror
B. 60 cm behind the mirror
C. 60 cm in front of the mirror
D. none of the given answers
