The correct option is 15 km towards North.

Let us analyze the step-by-step movement of Manish starting from Point A on a standard 2D Cartesian coordinate plane where Point A is at the origin $(0,0)$.

Step 1: Start at Point A
Initial coordinates: $(0,0)$

Step 2: Drives 12 km towards East
Moving East increases the x-coordinate by 12 km.
New position: $(12,0)$

Step 3: Takes a left turn and drives 5 km
Facing East, a left turn means driving North, which increases the y-coordinate by 5 km.
New position: $(12,5)$

Step 4: Takes a left turn and drives 30 km
Facing North, a left turn means driving West, which decreases the x-coordinate by 30 km.
New position: $(12-30,5)=(-18,5)$

Step 5: Takes a left turn and drives 20 km
Facing West, a left turn means driving South, which decreases the y-coordinate by 20 km.
New position: $(-18,5-20)=(-18,-15)$

Step 6: Takes a final left turn, drives 18 km and stops at Point Q
Facing South, a left turn means driving East, which increases the x-coordinate by 18 km.
Coordinates of Point Q: $(-18+18,-15)=(0,-15)$

Finding the distance and direction to reach Point A from Point Q:
Point A is at $(0,0)$ and Point Q is at $(0,-15)$.
The difference in x-coordinates is 0 km.
The difference in y-coordinates is:

$0-(-15)=15\text{km}$

Since Point Q is directly below (South of) Point A by 15 km, Manish needs to drive 15 km towards North to reach Point A again.