Amit started walking positioning his back towards the sun. After some time, he…

Direction-sense questions are solved with a fixed compass-rotation rule: relative to whichever way a person currently faces, a left turn rotates them 90 degrees anticlockwise and a right turn rotates them 90 degrees clockwise. Because the sun rises in the East and sets in the West, the phrase 'back towards the sun' fixes an absolute starting direction only once the time of day is fixed -- so this question must be traced separately for a morning start and an evening start before the final direction can be chosen.

Morning (sun in the East):

1. The sun is in the East, so standing with his back to the sun means Amit starts out facing West.

2. First turn (left) from West: rotating 90 degrees anticlockwise, he now faces South.

3. Second turn (right) from South: rotating 90 degrees clockwise, he now faces West.

4. Third turn (left) from West: rotating 90 degrees anticlockwise, he now faces South.

Final heading: South.

Evening (sun in the West):

1. The sun is in the West, so standing with his back to the sun means Amit starts out facing East.

2. First turn (left) from East: rotating 90 degrees anticlockwise, he now faces North.

3. Second turn (right) from North: rotating 90 degrees clockwise, he now faces East.

4. Third turn (left) from East: rotating 90 degrees anticlockwise, he now faces North.

Final heading: North.

Cross-check: over the three turns (left, right, left) the net rotation is -90 + 90 - 90 = -90 degrees, i.e. equivalent to a single left turn applied to the starting heading. A single left turn on the morning start (West) gives South, and on the evening start (East) gives North -- confirming both traces above by an independent route.

So depending on whether Amit starts walking in the morning or the evening, he ends up facing South or North respectively.