Answer:
The correct answer would be a. transpiration.
Pineapple plant practice Crassulacean acid metabolism (CAM) as an adaptation towards the arid conditions.
As an adaptation, they shut down their stomata during the day time and open at night time to collect carbon dioxide.
The closing of stomata during the day time reduces the loss of water through transpiration that is, the loss of water in the form of water vapours through stomata.