Correct Answer: C

Rationale: Ciprofloxacin, a fluoroquinolone, is the recommended first-line antibiotic for treating anthrax exposure due to its efficacy against Bacillus anthracis, the bacteria causing anthrax. Amoxicillin/clavulanate is a broad-spectrum antibiotic but not preferred for anthrax. Nystatin is an antifungal and ineffective against bacterial infections. Tamoxifen is used for breast cancer and has no role in treating anthrax.

Correct Answer: A,B,D,E

Rationale: Chemotherapy targets rapidly dividing cells, causing alopecia (hair loss), bone marrow suppression (reducing blood cell production, increasing infection and bleeding risks), bleeding (due to low platelets), and nausea (from gastrointestinal irritation and vomiting center activation). Extrapyramidal symptoms are associated with antipsychotics, not chemotherapy.

Correct Answer: B

Rationale: Sulfamethoxazole/trimethoprim can increase potassium levels, and captopril, an ACE inhibitor, also raises potassium, increasing the risk of hyperkalemia. Uterine cancer, osteoporosis, and multiple sclerosis do not contraindicate its use.

Correct Answer: C

Rationale: Methotrexate is an antimetabolite that inhibits dihydrofolate reductase, an enzyme involved in folic acid synthesis, impairing DNA synthesis critical for rapidly dividing cells like those in leukemia. It does not stop fungal growth, alter pH levels, or specifically inhibit helper T cells (a mechanism associated with immunosuppressive drugs like cyclosporine).

Correct Answer: A

Rationale: Chloroquine is associated with retinal toxicity, which can cause vision changes or damage, necessitating regular eye exams. It is not linked to tumors, pancytopenia, or cancer.