Try it
Pick an option and check your answer. The full worked answer is below either way.
Answer
(c) It is the loss of water in the form of water vapour from the aerial parts of the plant..
Two elements must both be right, and each wrong option fails on one of them: the water is lost as WATER VAPOUR — which rules out option (a), since DROPLETS are GUTTATION, a different process altogether it is lost from the AERIAL parts — which rules out (b), the underground parts, and (d), all parts
OPTION (d) IS THE CLOSEST TRAP. Roots do not transpire; they ABSORB water. Saying "all parts" would include them and is therefore wrong, even though it sounds more complete.
The three kinds of transpiration are all from aerial parts: STOMATAL (leaves, about 90%), CUTICULAR (the waxy cuticle) and LENTICULAR (lenticels of woody stems).
Fix the pair permanently: TRANSPIRATION gives water VAPOUR through STOMATA; GUTTATION gives water DROPS through HYDATHODES.
It is the loss of water in the form of water vapour from the aerial parts of the plant..