That whenever any form of government becomes destructive of these ends, it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness.

which idea does this excerpt support?

a. all members of a community should have the right to vote for their leaders.
b. democracy is the best form of government for protecting citizens' natural rights.
c. citizens must be allowed to overthrow a government that does not protect their rights.
d. no government can possibly protect the rights of all of its citizens.

 C.  Citizens must be allowed to overthrow a government that does not protect their rights.

Context/details:

The quote you referenced comes from the Declaration of Independence.  In preparing that document, Thomas Jefferson and the American patriots were asserting their right to govern themselves and throw off the government of the British monarchy.   The American founding fathers got ideas like this from the Enlightenment philosopher John Locke.  According to Locke's view, a government's power to govern comes from the consent of the people themselves -- those who are to be governed.  In his Second Treatise on Civil Government, Locke argued for the rights of the people to create their own governments according to their own desires and for the sake of protecting their own life, liberty, and property.  This also meant the right to change a government if the existing government did not protect those rights.