Statement-A : Light rarely becomes a limiting factors for plants growing in dense forests.Statement-B :The current concentration of CO2 in the atmosphere is limiting for most of the plants.The correct option is

Except for plants in shade or in dense forests, light is rarely a limiting factor in nature.Carbon dioxide is the major limiting factor for photosynthesis. The concentration of CO2 is very low in the atmosphere (between 0.03 and 0.04 per cent). Increase in concentration upto 0.05 per cent can cause an increase in CO2 fixation rates; beyond this the levels can become damaging over longer periods.