Please. Provide explanation for each term and also the correct answer

Solution 

Mutated means a change in the genetic composition due to mutagens. 
Embolised means a break in water column due to disconnection between xylem and phloem.
Etiolated means turning pale due to lack of light.
Defoliated means when the plant loses all its leaves. 

Thus in this question, the correct answer will be C - etiolated.