Here's a problem to solve: A student observes that a plant grows at different rates at different times. The student states that these changes must result from changes in the amount of light received by the plant. Which description of the student's statement is most accurate?

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

- A: It is an opinion and not a fact.
 
- B: It is correct because it is based on observation.
 
- C: It is one of several possible explanations for the evidence.
 
- D: It is invalid because it is not based on a scientific method.
 