Risperidone can raise prolactin levels because it blocks dopamine D2 receptors, including in the tuberoinfundibular pathway that normally keeps prolactin in check. When this dopamine inhibition is blocked, prolactin secretion increases, leading to breast tissue growth and milk production—gynecomastia and lactation. This hormonal effect is a hallmark of risperidone’s side effects, making it the best choice. Weight changes can occur with antipsychotics, but “massive weight gain” isn’t the most characteristic side effect of risperidone. Slowing the heart rate isn’t a typical or defining effect of this medication, and risperidone does not require taking with food for efficacy; it can be taken with or without food.

Encephalitis is typically spread by arthropod vectors that carry viral agents and transmit them to humans during feeding. Ticks can transmit tick-borne encephalitis and related viruses, while mosquitoes carry a variety of encephalitic viruses such as West Nile and Japanese encephalitis. Because of this, the vectors most commonly associated with transmitting encephalitis are ticks and mosquitoes. The other pairings don’t fit: fleas and lice mainly transmit diseases like plague or typhus, snails and slugs are hosts for certain parasites but not encephalitis, and cockroaches are not known vectors for these viruses.

When replacing potassium, the ability of the kidneys to excrete potassium is the deciding factor. IV potassium is concentrated and can rapidly raise serum potassium if renal function is poor, so you must confirm the patient is producing urine before giving IV potassium. If there is little or no urine, administering IV potassium risks dangerous hyperkalemia and arrhythmias, so IV potassium should be delayed until urine output is established and renal function is adequate. In adults, a practical check is ensuring a minimum urine output (about 0.5 mL/kg/hour) before starting IV replacement, and then administering potassium cautiously with continuous monitoring. Oral potassium can be used when renal function is adequate and slower correction is acceptable, but it won’t be appropriate if the patient isn’t producing urine or needs rapid stabilization. Potassium is indeed required in hypokalemia, so choosing not to replace it would be incorrect.

Paroxetine is an SSRI, and the question asks which option corresponds to Paroxetine itself. Among the listed drugs, the one that matches Paroxetine is Paroxetine, since it is one of the SSRIs. The other names are different SSRIs (fluoxetine, sertraline, citalopram) and do not describe Paroxetine.