Track his position step by step starting at (0,0). Step 1: walks north 12 m → (0, 12). Step 2: turning right while facing north means he now faces east; walks 5 m → (5, 12). Step 3: 'opposite direction' of east is west; walks 10 m → (5-10, 12) = (-5, 12). Step 4: he was facing west, turning left means he now faces south; walks 12 m → (-5, 12-12) = (-5, 0). His final position (-5, 0) is exactly 5 m from the starting point (0,0). Answer: 5 m, option (3).