All A are B. Some C are A. What can be concluded about Some C are B?

• A. Some C are B
• B. All C are B
• C. No C are B
• D. Some B are C

Answer: (A)

When all A are B, A sits inside B. If some C are A, there are elements that are both C and A. Those elements, being A, are also B. So there exists something that is both C and B, meaning some C are B. You can’t deduce that all C are B from this information, and no C are B would contradict the existence of that shared element.