下列溶液中离子浓度的关系一定正确的是（　　）

A．Na₂CO₃和NaHCO₃溶液中：c（Na⁺）+c（H⁺）=c（OH^-）+c（HCO₃^-）+c（CO₃^2-）

B．一元弱碱MOH对应的盐MCl溶液中：c（Cl^-）＞c（H⁺）＞c（M⁺）＞c（OH^-）

C．等物质的量的一元弱酸HX与其钾盐KX的混合溶液中：2c（K⁺）=c（X^-）+c（HX）

D．pH=3的一元酸HX和pH=11的一元碱MOH等体积混合：c（M⁺）=c（X^-）＞c（H⁺）=c（OH^-）

Time flies as an arrow. I’m already in the second half of senior Grade 3 before I realized it. it 

is only a little more than three months before I graduate middle school. At the present. I’m busy

review my lesson in order to take the college entrance examination. I hope to go to Beijing

Universiv, that is one of the best university not only in China but also in the world. I’ll try my best

to turn my dream into reality. Most of my classmates are also studying very hard to realize our

wishes I do believe everyone will able to enter a very good university and college.