A 29-year-old male patient with shift work disorder exhibits excessive daytime sleepiness that is interfering with his ability to perform duties as a customer service agent. He is initiated on armodafinil with good therapeutic response. Modafinil and its R-enantiomer, armodafinil, are hypothesized to promote wakefulness and increase alertness by:
a) Inhibiting dopamine reuptake
b) Blocking norepinephrine transporters
c) Increasing GABAergic transmission
d) Enhancing serotonin release
