Nitrogenous waste is excreted in the form of pellet or paste by :
Salamamdra
Hippocampus
Pavo
Ornithorhyuchus
Nitrogenous waste excreted in the form of pallets is uric acid (since it is insoluble in water). This is seen in class Aues. Hence option 3 pave is the answer
Hence, Option (3) is correct.