Question: Of all the groups of drugs listed below, those that less frequently provoke an anaphylactic reaction in the patient are: 
 Options:  <1> The NSAIDs. <2> Opioid analgesics. <3> Contrast media containing iodine, used for radiological examinations. <4> The benzodiazepines. <5> Antibiotics, especially penicillins, cephalosporins and sulfonamides.
4