<prompt>  Which of the following statements best describes the mechanism of action of benzodiazepines ?Benzodiazepines activate GABAB receptors in the spinal cordBenzodiazepines block glutamate receptors in neuronal pathways in the brainThey increase the frequency of opening of chloride ion channels that are coupled to GABAA receptorsThey are direct acting GABA receptor agonists in the CNS 