The correct options are
A Liberation from colonial rule
B Crisis situation post a dictatorial rule
C End of Apartheid
A constitution is usually demanded when a nation reaches a crisis point or when colonial rule ends in a country. It is at times like these that the call for a new constitution is the loudest. For example, the end of Apartheid in South Africa, or the end of British rule in India. A natural disaster is a natural event and it's occurence does not result in a request for a brand new constitution.