How Far from a +50-Mm Focal Length Lens, Such as Is

Multiple Choice

How far from a +50-mm focal length lens, such as is used in many 35-mm cameras, must an object be placed so it will form a real image that is 3.0 times the size of the object?

A) 58 mm
B) 67 mm
C) 46 mm
D) 52 mm