Which global threat emerged in iraq more than 10 years after the toppling of saddam hussein?

The United States invaded in Iraq and fall down Saddam Hussein in 2003. This led to the emergence of chaos and the eventual rise of Al Qaeda as the global threat.

When United States troops or army left Iraq in 2011 all the terrorist groups were largely defeated and almost merged into ashes. But as soon as the army left Islamic state managed to rise from its ashes and capture the northern and western part of Iraq in just two years. Now the country is on the verge of repeating terrorist activities, civil war, violence, insurgence.  

In 2017 premium terrorism organization ISIS was largely routed but the seeds of terrorism were down a while ago. Even after ten years of decline of Saddam Iraq is still discovering mass graves in which the major part is of their own people that died because of civil war or in terror activities.

#2 the answer is d

#3 the answer is a

#4 the answer is b