The correct answer is D. They have created instability by carrying out attacks and political uprisings.
Several radical Islamist groups have accumulated great power in the Middle East during the last decades.
Islamism comprehend a wide range of political ideologies that seek to adapt public and political life to the precepts of Islam, or at least to their interpretations of what those precepts are. Many radical Islamist groups tend to do so by any mean, even using violence and terror against Muslim and non-Muslim populations. The largest attack in the West by one of these terrorist groups, Al-Qaeda, was the attack against the World Trade Center in 2001.
After this event, the United States declared the war against terrorism and started the invasion of Afghanistan in 2001, in order to overthrow the Taliban regime. Two years later the war of Iraq took place, its objective was to overthrow the regime of Saddam Hussein, which was not Islamist but anti-American. This goal was accomplished, but it created a vacuum of power in Iraq, which was taken as an advantage by radical Islamist groups that spread all over Iraq.
With the instability that took over Syria after the Arab Spring, many of these groups entered in Syria from Iraq and deepened the ongoing civil war. In 2014 a new radical Islamist group that nucleated many others declared an Islamic State in Iraq and Syria (ISIS) as the Caliphate of all Muslims. This terrorist group tends to expand its frontiers and committed many atrocities since then.
Other radical Islamist groups are implicated in ongoing conflicts and recurrent attacks in Yemen, Palestine, Israel, Lebanon, and Libya. Many of the political uprisings of the Arab Spring were supported by Islamist (not necessarily terrorist/radical) groups and parties, like the Muslim Brotherhood in Egypt.