On the basis of body covering, Rohit made four groups of three organisms each. In an attempt of doing so, he classified organisms incorrectly in one of the groups. Identify this group and select the correct option. 
 
ATortoise, Snail, Oyster 
BFish, Snake, Lizard 
CPenguin, Ostrich, Bat 
DHippopotamus, Whale, Cow
why c is answer
 
             
             
        