Which of the following represents the correct combination without any exception?

	Characteristics	Class
1.	Sucking and circular mouth; jaws are absent; integument without scales; paired appendages	Cyclostomata
2.	Body covered with feathers; skin moist and glandular; forelimbs form wings; lungs with air sacs	Aves
3.	Mammary gland; hair on body; pinnae; two pairs of limbs	Mammalia
4.	Mouth ventral; gills without operculurn; skin with placoid scales; persistent notochord	Chondrichthyes

In Chondrichthyes, mouth is ventral, gills lack operculum, skin has placoid scales, notochord is persistent.

Note: There are exceptions like Chimera which has an operculum covering the gill-slits on each side. Such an exception must be ignored while selecting the most appropriate answer. 

Cyclostomes do not have paired appendages.

In birds, skin is dry and without glands, except for the oil gland present at the base of the tail.

In mammals, pinnae are absent in some (e.g., monotremes, whales, dolphins). Two pairs of limbs are not present in all e.g., in whales, forelimbs are modified into flippers and hindlimbs are vestigial.