Write the following statement as a biconditional.
A heptagon is a seven-sided polygon.

Choose the correct answer below.
OA. A figure is a heptagon if and only if it is a seven-sided polygon.
OB. A figure is a heptagon if and only if it is not a seven-sided polygon.
OC. If a figure is a heptagon, then it is a seven-sided polygon.
OD. If a figure is a seven-sided polygon, then it is a heptagon.