Submitting property offer under drugs

A person under the influence of drugs submits an offer to purchase property.  The offer can be best described as:

  1.  discharged
  2.  fraud
  3.  voidable
  4.  valid

The answer is C.  The best description for this is that the offer is voidable, because when the buyer is not under the influence of drugs he/she can decide whether or not to go through with the offer.