First Muslim Head of Pakistan Army:

The correct answer is General Ayub. General Muhammad Ayub Khan was the first Muslim Commander-in-Chief of the Pakistan Army, taking over from General Sir Douglas Gracey in 1951. He later became the second President of Pakistan.

• General Yahya: General Yahya Khan succeeded Ayub Khan as President and Commander-in-Chief much later.
• General Zia-ul-Haq: General Zia-ul-Haq became the Chief of Army Staff and later President much later in Pakistan's history.
• None of these: This is incorrect as General Ayub Khan was indeed the first.

This question tests knowledge of key figures in Pakistan's early military and political leadership.