What protects federal judges from political pressure to make a certain ruling?

AFederal judges can have anyone arrest them who threatens them.

BFederal judges serve for life, and so do not need to worry about conforming to the wishes of others to be reelected.

CFederal judges vote in blocks and have little power to sway the opinions of the other judges.

DFederal judges only hear cases in private so they are not subjected to outside influences.