Direction problems like this are easiest to track by assigning a compass bearing to each leg and turning it by 90 degrees for every left or right instruction, rather than picturing the walk itself. Start Manoj facing North, which we can call a bearing of 0 degrees.
He walks 5 m North (bearing stays 0 degrees), then turns to face East, a 90-degree turn, so his bearing becomes 90 degrees, and he walks 10 m. Next, he turns right. A right turn always adds 90 degrees to the current bearing, so 90 + 90 = 180 degrees, which is South, and he walks 15 m facing South. Finally, he turns left. A left turn always subtracts 90 degrees from the current bearing, so 180 - 90 = 90 degrees, which is East again, and he walks 15 m facing East.
Following the bearing through all three turns confirms Manoj ends the walk facing East.
Therefore, the correct answer is East.
Instead of tracking compass bearings in degrees, we can represent each facing direction as a small arrow, North as (0, 1), East as (1, 0), South as (0, -1), and West as (-1, 0), and use the rule that turning right rotates the arrow using \( (x, y) \to (y, -x) \), while turning left rotates it using \( (x, y) \to (-y, x) \). Manoj starts facing North, so his direction arrow is (0, 1), and he walks 5 m.
He then turns to face East, giving the arrow (1, 0), and walks 10 m. Next, he turns right: applying \( (x, y) \to (y, -x) \) to (1, 0) gives (0, -1), which is South, and he walks 15 m facing South. Finally, he turns left: applying \( (x, y) \to (-y, x) \) to (0, -1) gives (1, 0), which is East again, and he walks 15 m facing East.
Tracking the direction as a rotating arrow through each turn confirms Manoj ends up facing East.
Therefore, the correct answer is East.