Which of the following died of Natural Death?

Indira Gandhi was Prime Minister of India and daughter of Jawaharlal Nehru. She was killed by her Sikh bodyguard Satwant Singh.
Rajiv Gandhi was killed was Prime Minister of India and son of Indira Gandhi. He was killed in a Suicide Bomb Attack.
Mahatma Gandhi (Mohandas Karamchand Gandhi) was killed by Hindu Fanatic Nathu Ram.