The correct answer is A) to ensure individual freedoms.
The 9th amendment essentially states that any right not given specifically to the government is retained by the people. The implementation of this amendment was rooted in the fears of American citizens who worried about a tyrannical central government that would take away the rights of citizens. This paranoia about a strong central government really originated due to America's relationship with the British during the late 18th century.
This is why when America became independent, they tried to create a government structure in which the central government was extremely limited in its scope.
