Immediately after the attacks of september 11, 2001, many people around the world a. felt uncomfortable voicing support for the united states. b. were shocked by the events and condemned the attacks. c. declared war on al-qaeda and other terrorist organizations. d. remained silent to avoid attacks by al-qaeda on their soil

It's C

Declared war on al-Qaeda and other terrorist organizations.

Explanation:

September 11 attacks were four terrorist attacks against US, it was carried bout on September 11, 2001 by members of Al-Qaeda and led to death of more than 2800 victims and loss of ten billion in infrastructure and property.

World leaders, political and religious personalities and media, all condemned the attacks.Even the countries which had bitter relations with US condemned it, some countries also celebrated the attacks. Various groups accused the country for bringing the attack on itself. Many countries froze the bank accounts if the people suspected of related with the Al-Qaeda, anti-terrorism legislation were also introduced.

d.

the northwest territory became the most densely populated area in the u.s.