A depressed patient is given a drug X that raises the effective level of noradrenaline in the body. Which description of X is consistent with the mechanism of drugs such as iproniazid?

1. AIt inhibits the enzymes that break down noradrenaline, so the neurotransmitter stays active longer
2. BIt destroys the receptors on which noradrenaline acts
3. CIt blocks the release of noradrenaline from nerve endings
4. DIt neutralises noradrenaline as an antacid would