Social networking is based on the six degrees of concept which posits that you can connect with anyone through a chain of no more than six introductions or personal links.

The correct answer in the missing blank is known as "separation".

The six degrees of separation is known as a theory in social networking wherein it states that a person can be connected anyone in the world, no matter how far, through a process of acquaintances, which possesses not more than five mediums.

The correct answer is a.f.c