Social Security Has Been Called the Third Rail of Politics,which

Social Security has been called the third rail of politics,which means:

A) it is a program spending more than it is taking in
B) it is a program taking in more than it is spending
C) politicians propose frequent changes to it in order to appease their constituents
D) politicians do not like to propose changes because they would likely be unpopular with their constituents
E) major changes have regularly been made to the policy