Why did the united states and its allies use force against afghanistan following the attacks on september 11, 2001? its government was responsible for the attacks. its government would not hand over bin laden. osama bin laden had fled there after the attacks. all the 9/11 hijackers were from afghanistan.

Option C: Osama bin Laden had fled there after the attacks.

The US-led war in Afghanistan began on October 7, 2001, as Operation Enduring Freedom. It was designed to capture or kill Osama bin Laden and al-Qaeda militants, as well as replace the Taliban with a US-friendly government.

Side note: Two of my uncles were marines specializing in breaching and cqb, and another two were pilots, one flying Apaches and another A-10s during this time.

b. by enlisting in the military to fight

yup! you are correct it is b.