Solution:Concept: CAM plants are mostly xerophytes, developing in deserts. They open their stomata amid the night and settle climatic carbon into natural acids, like oxaloacetic corrosive and malic corrosive.
These natural acids are by and large four carbon molecules containing compounds. During daytime the natural acids are decarboxylated to discharge carbon dioxide, which is settled through RuBisCo and regular Calvin cycle. The opening of stomata amid night time could be a physiological adjustment to avoid the misfortune of water through transpiration.
Hence, the correct answer is option 3.