Which condition will create a gap at a vertex of polygons?

the sum of the measures of the angles is less than 360°.

the sum of the measures of the angles is greater than 360°.

the sum of the measures of the angles is equal to 360°.

The  

for answering this question, we have exactly to cases:

case 1: if the polygons are regular 
           so the answer is 
  
The sum of the measures of the angles is equal to 360°.

for example, let's consider the quadrilateral polygone ( the four sides are congruent and each angle measures 90°)
so the sum of the angle is  90° +90°+90°+90°= 360°

case 2
if the polygons are not regular (irregular)

the answer is 

The sum of the measures of the angles is greater than or less than 360°.

for example, if we consider an irregular polygon of 7 sides that not congruent, and each angle are not congruent, so the sum of the measures of the angles must be greater than or less than 360°