The Onam festival is celebrated to commemorate the Vamana avatara of Vishnu. The Vaman avatara was Vishnu’s __:
[A]Third Avatara
[B]Second Avatara
[C]Fifth Avatara
[D]Sixth Avatara

Fifth Avatara
The 10-day-long Hindu festival, Onam is celebrated with a great enthusiasm throughout Kerala between August and September. It is celebrated to honour King Mahabali, who according to legend ruled the state once, under whom the people were equal, prosperous and happy. As per the mythology, people believe that it was on this particular day of Thiruvonam in the Malayalam calender month of Chingam when Lord Mahavishnu took his fifth avatar as Vaamana, appeared in the kingdom of King Mahabali and sent him to the netherworld. So, as per the legends, on this day, the spirit of King Mahabali visits the people of Kerala and to welcome him, people decorate their homes with flowers, etc.