Which among the following died of a natural death?

Jawaharlal Nehru died of natural causes relating to heart trouble on May 27, 1964; he had been in poor health since 1962. Internal medical causes were the reasons for his death, not violence. Causes of death of all these: (A) Mahatma Gandhi - assassinated (shot) by Nathuram Godse on January 30th, 1948, in New Delhi. (B) Indira Gandhi - assassinated by shooting on October 31, 1984, in New Delhi by her bodyguards. (C) Jawaharlal Nehru — died of a heart attack/suspected stroke/heart failure on 27 May 1964. (D) Rajiv Gandhi — killed in a suicide bomb attack on May 21, 1991, in Sriperumbudur, Tamil Nadu.