The real image of an object is located 45.0 cm away from a concave mirror, which has a focal length of 10.0 cm.How far is the object from the mirror?

The real image of an object is located 45.0 cm away from a concave mirror, which has a focal length of 10.0 cm.How far is the object from the mirror?
A)40.0 cm
B)35.0 cm
C)22.5 cm
D)12.9 cm