Here's a problem to solve: Which of the following statements is a scientific hypothesis?

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

- A: Flossing has proven to be an effective method of improving oral health.
 
- B: Many infectious diseases, such as gum disease, are caused by microorganisms.
 
- C: In general, any method that reduces bacteria in the mouth will improve oral health.
 
- D: An individual who flosses daily will be less likely to get gum disease than one who flosses weekly.
 