Why are public properties being serialized w/ an underscore in MVC4?

[abbi]

In the following class\[code\]using System;namespace Beverati.Repository.ViewModel{[Serializable]public class CollectionItem : EditableEntityBase{public CollectionItem() {}private int? _quantity;private string _retailValue;private string _currencyName;public int? quantity{ get { return this._quantity ?? NULL_INTEGER; } set { this._quantity = value; }}public string retailValue{ get { return this._retailValue ?? String.Empty; } set { this._retailValue = http://stackoverflow.com/questions/14062364/value; }}public string currencyName{ get { return this._currencyName ?? String.Empty; } set { this._currencyName = value; }}}}\[/code\]returned in this controller action\[code\]public IEnumerable<Repository.ViewModel.CollectionItem> GetAll()\[/code\]produces this JSON output with MVC2 the JSON output like this\[code\]{ quantity:2 retailValue: 50.00 currencyName: USD}\[/code\]However, when I installed MVC4 the JSON returned looks like this\[code\]{ _quantity:2 _retailValue: 50.00 _currencyName: USD}\[/code\]All the property names have an underscore prefix. Why is the underscore being used and what should be done to have the public property names returned in the JSON?