example of closure?

1.js

function A() {
  var x = 1;
  C(B);
  
  function B() { console.log(x); }
  
  function C(callback) {
    B === callback;      // true
    
    B();                 // is this console.log() using a closure or not? depends on perspective.
    callback();          // ditto
  }
}

A();
// 1
// 1