The word “AMBULANCE” is painted in reverse as “ECNALUBMA” on the front of emergency vehicles. What is the main reason for this practice?
(a) It prevents glare from oncoming headlights.
(b) It appears correctly oriented in drivers’ rear-view mirrors.
(c) It compensates for the convex shape of rear-view mirrors which would otherwise compress the letters.
(d) It ensures the letters are upright because mirrors invert images vertically.