Here's a problem to solve: The rate of growth for a species of grass was measured in a treeless yard and tree-shaded yard. The grass grew twice as fast in the treeless yard. Which factor most likely contributed to the difference in growth rate?

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

- A: amount of animals
 
- B: amount of light
 
- C: amount of soil
 
- D: amount of rain
 