As your boss ushers you into his office and closes the door, you experience a strong surge of the fight-or-flight response. But since you can't fight and you can't flee, all of that energy is pent-up inside of you with no place to go. You feel like you're going to explode.



 As it is used in this passage, the expression "pent-up" means

A)renowned.B)released.C)held back.D)prohibited.