—Excuse me, what can I do for you?

—Yes. I'd like to place ____ advertisement for _____ used car in your paper.

A．the; a

B．an; /

C．an; a

D．/; the

下列各组离子在pH=1的溶液中能大量共存的是（　　）

A．Na⁺、Cl^-、OH^-

B．K⁺、Ca²⁺、CO₃^2-

C．Ag⁺、Na⁺、Cl^-

D．NO₃^-、Mg²⁺、Cu²⁺