which of the following was the minimum requirement of the U.S. Constitution to go into effect?

a 6 of 13 states had to ratify it
b 9 of 13 states had to ratify it
c 11 of the 13 states had to ratify it
d all 13 states had to ratify it

The correct answer is b) 9 of 13 states had to ratify it.