Return data in Json format with object name

Wrote a simple function for Web API 2 which returns the list of countries. It returns the valid Json format but without the array/object name. I have a bit of difficulty understand how this is achieved?

Here is my C# code:

[Route("Constants/CountryList")]
[HttpGet]
public IHttpActionResult GetCountryList()
{
    IEnumerable<ISimpleListEntity> list = new CountryStore().SimpleSortedListByName();
    if (list == null || !list.Any())
    {
        return NotFound();
    }

    return Ok(list);
}

ISimpleListEntity interface code is here.

public interface ISimpleListEntity
{
    int Id { get; set; }
    string Name { get; set; }
}

This service returns the following Json output (without the object/array name):

[  
   {  
      "Id":1,
      "Name":"[Select]"
   },
   {  
      "Id":4,
      "Name":"India"
   },
   {  
      "Id":3,
      "Name":"Singapore"
   },
   {  
      "Id":2,
      "Name":"United Arab Emirates"
   }
]

But, am struggling to achieve the following Json format (WITH the object/array name called 'CountryList'):

{  
   "CountryList":[  
      {  
         "Id":1,
         "Name":"[Select]"
      },
      {  
         "Id":4,
         "Name":"India"
      },
      {  
         "Id":3,
         "Name":"Singapore"
      },
      {  
         "Id":2,
         "Name":"United Arab Emirates"
      }
   ]
}