A $120$ cm pointer is placed perpendicular to a plane mirror. The $0$ cm end is farther from the mirror, and the $120$ cm end is $18$ cm from the mirror. What is the distance between the real $40$ cm mark and the image of the $90$ cm mark?

• A. $128$ cm
• B. $146$ cm
• C. $156$ cm
• D. $168$ cm

Answer: (B)