4.(2020·济南高二检测)离子晶体熔点的高低决定于阴、-|||-阳离子间离子键的强弱,据所学知识判断KCl、NaCl、-|||-CaO、BaO四种晶体熔点的高低顺序是 ()-|||-A. gt NaClgt BaOgt CaO-|||-B. gt KClgt CaOgt BaO-|||-C. gt BaOgt KClgt NaCl-|||-D. gt BaOgt NaClgt KCl