Speaker A: Excuse me. I'd like to exchange this watch. I just bought it, but look at this.Speaker B: ______

A．Yes, I know your watch is new, but I like my old one better.

B．What seems to be the problem

C．Thank you for your kindness, but my watch still works.

D．Sorry. Why didn't you examine it carefully before you bought it

将下列各组物质放入足量水中，有化学反应发生，但无沉淀生成，也无气体放出，且溶液为无色的一组是（　　）

A．K₂CO₃、BaCl₂、NaCl

B．CuSO₄、HNO₃、NaCl

C．CaCl₂、KOH、Na₂CO₃

D．K₂SO₄、H₂SO₄、NaOH