Which amendment to the Constitution of Pakistan abolished the office of the President and established a parliamentary system of government?

Correct Answer: D: 18th Amendment

Explanation: The correct answer is the 18th Amendment, which abolished the office of the President and established a parliamentary system of government in Pakistan. This amendment was passed in 2010 and marked a significant shift in Pakistan's constitutional framework. Options like the 8th Amendment are incorrect, as they refer to a different amendment. The 18th Amendment is an essential part of Pakistan's constitutional history, as it has had a lasting impact on the country's system of government. This topic appears in various FPSC, CSS, and NTS exams, testing candidates' knowledge of Pakistan's constitutional framework.