SELECT TOP 1
         ID,Code,JSON_QUERY(B.[value]) AS options
FROM OPENJSON(Json) WITH (ID nvarchar(max),Code nvarchar(max),Json nvarchar(max), options NVARCHAR(MAX) AS JSON) D
CROSS APPLY OPENJSON(D.Json) B
ORDER BY B.[key] DESC
FOR JSON PATH, WITHOUT_ARRAY_WRAPPER;

{"98934889":"Date: 08/16/2017","5551099988":"This is First comment","5454454545":"This is Second comment"}