如何实现C类？

Question

var A = function(name){  this.name=name;}A.prototype = {  sayName:function(){    alert(this.name);  }}var B = function(age){  this.age = age;}B.prototype = {  sayAge : function(){    alert(this.age)  } }//function C(){};var c = new C("white",25);c.sayName();c.sayAge();