A Light Bulb Burns in Front of the Center of a 40-Cm

A light bulb burns in front of the center of a 40-cm wide mirror that is hung vertically on a wall. A man walks in front of the mirror along a line that is parallel to the mirror and twice as far from it as the bulb. The greatest distance he can walk and still see the image of the bulb is:

A) 20 cm
B) 40 cm
C) 60 cm
D) 80 cm
E) 120 cm