How to form a request body to POST(method) a json in C#

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C#

JSON

REST

Hi, Attached below is the reqst JSON. can any one help me on generating/ creating a request body for the same.

{
  "groups": [{
      "groupName": "abc",
      "questions": [{
          "questionID": "",
          "groupedIndexVlaue": 2,
          "indexvalue": 6
        }, {
          "questionID": "",
          "groupedIndexVlaue": 2,
          "indexvalue": 6
        }

      ]
    }, {
      "groupName": "xyz",
      "questions": [{
          "questionID": "",
          "groupedIndexVlaue": 2,
          "indexvalue": 6
        }, {
          "questionID": "",
          "groupedIndexVlaue": 1,
          "indexvalue": 7
        }
      ]
    }
  ]
}

I need the request body like below to work with post method. Please any one suggest me how to form the request body as per the above Json.

{
  "Items": [{
      "questionID": 1,
      "groupedIndexVlaue": 5,
      "indexvalue": 5
    }, {
      "questionID": 2,
      "groupedIndexVlaue": 5,
      "indexvalue": 5
    }

  ]
}

Thanks.

What I have tried:

Attached below is the reqst JSON. can any one help me on generating/ creating a request body for the same.