Question du test Javascript

Soit le code suivant :

function MyObject() {
  this.one = function() {
    return 1;
  };
  function two() {
    return 2;
  };
}

MyObject.prototype.three = 3;
MyObject.four = 4;

var obj = new MyObject();
try { console.log(obj.one()); } catch(e) {}
try { console.log(obj.two()); } catch(e) {}
try { console.log(obj.three); } catch(e) {}
try { console.log(obj.four); } catch(e) {}