In the given question, a statement of Assertion is followed by a statement of Reason. Mark the correct answer.

Assertion: US-backed the Islamic militants in Afghanistan against the Soviet Union in the 1980s but later attacked them after the 9/11 incident.

Reason: Alliances are based on national interests and can change when national interests change.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

Alliances are based on national interests and can change when national interests change. For example, the US backed the Islamic militants in Afghanistan against the Soviet Union in the 1980s, but later attacked them when Al Qaeda—a group of Islamic militants led by Osama bin Laden—launched terrorist strikes against America on 11 September 2001