Ans . Karan
Karan was eldest son of Kunti but he was not among the 5 Pandavas.
Pandava’s were sons of Pandu.
Kunti was blessed to have sons from any God with a powerful mantra which she gained after serving Rishie Durvasa.
Kunti decided to test the mantra out of her curiosity ,She summoned God Surya (Sun). The God Surya appeared and blessed her to have his sun Karan. Kunti was afraid to unveil Karan because she was unmarried ,so she abandoned him in a basket in a river. The basket reached a chariot driver who was bathing in the river he was amused to see the child with Kavach and Kundal . Karan was born with Kavach and kundal as a blessing from his father Surya ,which will protect him. The chariot diver adopted Karan.