A- a regular heptagon
b- an irregular convex heptagon
c-an irregular concave heptagon
d- a complex heptagon

C. an irregular concave heptagon

Explanation:

Before we begin, we should define the terms used in the choices given:

1- Heptagon: It is the polygon that has 7 sides

2- Regular heptagon: It is a 7-sided polygon in which all sides are equal and all angles are equal

3- Irregular heptagon: It is a 7-sided polygon in which neither the sides nor the angles are equal

4- Concave heptagon: It is a 7-sided polygon in which one or more of its angles are more than 180°

5- Convex heptagon: It is a 7-sided polygon in which all its angles are less than 180°

6- Complex heptagon: It is a 7-sided polygon whose dimensions are in the complex plane

Now, let's check the given diagram:

It is a 7-sided polygon, therefore, it is a heptagon

It's sides as well as its angles are not equal, therefore, it is an irregular heptagon

It has interior angles measuring more than 180°, therefore, it is a concave heptagon

Its dimensions are not in the complex plane, therefore, it is not a complex polygon

Based on the above, the best choice is:

C. an irregular concave heptagon

Hope this helps :)

a and c

step-by-step explanation: