How do I return just 1 array for a JSON result.

[
    {
        "customer": 43563254,
        "points": 14
    }
]

public IEnumerable<Points> Get(int id)
        {
            _con = new SqlConnection("data source=SQLSERVER1;initial catalog=TRdb01;user id=sa");
            DataTable dt = new DataTable();
            var query = "Select top 1 customer, points from KR.Api_Points where customer = " + id;
            _adapt = new SqlDataAdapter
            {
                SelectCommand = new SqlCommand(query, _con)
            };
            _adapt.Fill(dt);
            //List<Points> pointsbal = new List<Models.Points>(dt.Rows.Count);
            List<Points> pointsbal = new List<Models.Points>(dt.Rows.Count);
     
            if (dt.Rows.Count > 0)
            {
                foreach (DataRow points in dt.Rows)
                {
                    pointsbal.Add(new readPoints(points));
                }
            }

            return pointsbal;
        }