Which of the Following Is True of Self-Control

Which of the following is true of self-control?

A) Failures of self-control are least likely to appear when one has to do something taxing,difficult,or unpleasant.
B) People who fail to exert self-control on a particular task subsequently work harder on other tasks.
C) Self-control can be depleted or strengthened,much like a muscle.
D) Self-control typically involves the strategy of humblebragging.