Final answer:
The addition of soap reduces the water surface tension at the point of contact, causing a floating matchstick to move towards an area with higher surface tension; the exact compass direction cannot be determined without context.
Step-by-step explanation:
The question seems to be about a simple physics experiment where a soap solution is added to water, and the effect on a nearby object, such as a matchstick, is observed. When a drop of soap solution is added, it causes the water surface tension to be reduced around the point of contact. If a matchstick is floating on the water surface, upon the addition of soap, the reduced surface tension behind the matchstick (at the point where the soap is added) compared to the higher surface tension in front of the matchstick will cause the matchstick to move towards the area of higher surface tension. However, the question does not mention the orientation of the compass directions (North, South, East, West) in relation to the setup. Hence, without this context, it is not possible to specify the direction as one of the compass points given (a, b, c, d).