Step 1: Understanding the Concept:
The question asks for the common characteristic among Indira Gandhi, Jawaharlal Nehru, and Benazir Bhutto.
Step 2: Detailed Explanation:
Indira Gandhi and Jawaharlal Nehru were Prime Ministers of India; Benazir Bhutto was Prime Minister of Pakistan. All three served as Prime Ministers of their respective countries.
Step 3: Final Answer:
Thus, the correct option is (B) They were Prime Ministers.