Based on the context you've provided, we can infer that photosynthesis is affected by the intensity of light, which is typically greater when the light source is closer.
Photosynthesis occurs in plants where carbon dioxide (CO2) and water (H2O) are converted into glucose and oxygen (O2) using light energy. As light intensity increases (i.e., when the light source is closer), the rate of photosynthesis typically increases, resulting in higher oxygen production and a reduction in carbon dioxide levels as it is consumed during the process.
Given this understanding, the correct inference would be:
d. The closer the light source, the higher the amount of oxygen gas produced.