A 7-year-old boy is brought to the ambulatory care clinic by his mother because of acting out in class and at home. In class, he often talks out of turn and does not stay focused on tasks. At home, his mother cannot get him to do his chores, and he never sits still. What is the most appropriate treatment for this patient?

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: Cisplatin is a platinum-based chemotherapeutic agent that exerts its cytotoxic effect by binding to DNA (A), forming intrastrand and interstrand cross-links. This disrupts DNA replication and transcription, leading to apoptosis of rapidly dividing cancer cells like small cell lung carcinomDNA polymerase is indirectly affected, not directly targeteGrowth factor receptors are targeted by tyrosine kinase inhibitors, reverse transcriptase by antiretrovirals, and ribosomes (E) by antibiotics like tetracyclines—none apply to cisplatin’s mechanism.

Correct Answer: A

Rationale: Bone marrow toxicity (e.g., myelosuppression) from chemotherapy occurs because marrow cells divide rapidly (A), making them highly susceptible to drugs targeting cell division (e.g., alkylating agents, antimetabolites). Specific targets apply to some drugs (e.g., imatinib), not most. ‘Used to prevent’ is unclear, nucleated cells aren’t the sole target (red cells lack nuclei), vascularity (E) aids delivery but isn’t the reason, and lipid solubility (F) varies by drug.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.