Here's a problem to solve: Which statement is an opinion about the heart?

Among the 4 following options, which is the correct answer?

- A: The primary function of the heart is to move blood through the body.
 
- B: The purpose of the heart is to help perform athletic activities.
 
- C: The rate of a beating heart can change throughout the day.
 
- D: The heart is composed of different types of cells.
 