Final answer:
Methylphenidate (Ritalin) would be expected to increase beta frequency activity, as it is a stimulant drug that leads to an increase in neuronal activity, which is associated with beta waves.
Step-by-step explanation:
The medication expected to increase beta frequency activity is a) Methylphenidate (Ritalin). Methylphenidate is a stimulant drug commonly used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy. Stimulants, such as amphetamines and methylphenidate, lead to an increase in neuronal activity and can therefore cause an increase in beta waves, which are associated with active, alert states of consciousness.
On the other hand, Lorazepam (Ativan) is a benzodiazepine which has a depressant effect on the central nervous system, typically reducing beta wave activity and promoting relaxation and reduction of anxiety. Olanzapine (Zyprexa) is an antipsychotic which also typically does not increase beta wave activity. Sertraline (Zoloft) is an antidepressant SSRI that primarily affects serotonin levels and is not typically known to increase beta wave activity either.