Class – Mammalia : 1. Heart is four- chambered. 2. Respiration is by lungs. 3. They are poikilothermous. Regarding 1,2 and 3:

Question

( a ) 2 is correct but 1 and 3 are incorrect
( b ) 3 is incorrect; 1 and 2 are correct
( c ) 2 is incorrect but 1 and 3 are correct
( d ) 1 is incorrect but 2 and 3 are correct