After the assassination of Prime Minister Liaquat Ali Khan in 1951, Ghulam Muhammad became the third Governor-General of Pakistan. He assumed office on October 17, 1951, succeeding Khawaja Nazimuddin, who became Prime Minister. Ghulam Muhammad served in this crucial role until 1955, during a period of significant political instability in the nascent nation.
Option B, Ghulam Muhammad, is the correct answer. He was a prominent figure who previously served as Finance Minister. Option A, Sikandar Mirza, became the fourth and last Governor-General in 1955, and later Pakistan's first President. Options C, Muhammad Ali Bogra, and D, Chaudhry Muhammad Ali, both served as Prime Ministers of Pakistan during different periods, not as Governor-Generals. Understanding the sequence of leadership is vital for comprehending Pakistan's early political history and the transition from dominion status to a republic.