Question

Five different forces act on an object. Is it possible for the net force on the object to be zero? Explain

Answer 1

No. If there are forces on an object, they need to have a counterforce, otherwise the object won't be zero. Since there are only 5 forces, the 5th force has no counterforce, resulting in movement or reforming the object.

Answer 2

Of course it is !

-- Whatever the resultant of four of the forces is, one more force
with the same magnitude in exactly the opposite direction makes
the overall net force zero.

-- Example: 
4 cheerleaders are in a tug-of-war against the captain of the football team.
The flag in the middle of the rope is stationary.
He's holding off all 4 of the skinny girls.
The net force on the flag is zero.