In my nodejs program, i have a module called person and it has a prototype object(about) which also has its child method (describe). I am trying to access objects properties but i am getting undefined. 

Could someone correct my understanding? what i am doing wrong here?

index.js
========

```
var Person = require("./person");
var sam = new Person({name:"Sam",age:23})
sam.about.describe();

```

person.js
=========

```
module.exports = (function() {
    var person = function(options) {
        if (options && options.name) this.name = options.name;
        if (options && options.age) this.age = options.age;
    }
    person.prototype.about = {
        describe : function(){
            console.log("I am",this.name,"and",this.age,"years old");
        }
    }
    return person;
})();

```

Expected output: "I am Sam and 23 years old"
Actual output: "I am undefined and undefined years old"