What is the name of the domain controller database that windows server 2012 r2 uses to store data about user access and resources on the network?

A Domain Controller is the Answer, it can be RO or RW.

answer(igmp);

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.