Which graph shows the effect of temperature on the rate of photosynthesis?

The answer is D.

The rate of photosynthesis keeps rising until 40 degrees Celsius. Above the temperature of 40 degrees, the enzymes responsible for photosynthesis lose their shape and cannot synthesize glucose anymore. Hence photosynthesis experiences a steep drop and around 50-60 degrees, the enzymes get completely destroyed hence photosynthesis stops completely.

The answer to this is B

B

Because the temperature acts as limiting agent as per the graphs shown