To find the sum of the interior angles of a regular heptagon, we use the formula for the sum of the interior angles of a polygon. The formula is:
[tex]\[
\text{Sum of interior angles} = (n - 2) \times 180
\][/tex]
where [tex]\( n \)[/tex] is the number of sides of the polygon. For a heptagon, [tex]\( n = 7 \)[/tex].
Plugging in the value:
[tex]\[
\text{Sum of interior angles} = (7 - 2) \times 180
\][/tex]
[tex]\[
\text{Sum of interior angles} = 5 \times 180
\][/tex]
[tex]\[
\text{Sum of interior angles} = 900
\][/tex]
So, the sum of the interior angles of a regular heptagon is 900 degrees. Therefore, the correct answer is:
C. 900