Split data then list them in the Dropdown list

Hi,

I have a dropdown list that list the following data like this. This is the output that I have right now.

<select name="CommitIDListID" class="btn btn-default dropdown-toggle" id="CommitIDListID" multiple="multiple">
    <option value="345456456, 553564646">345456456, 553564646</option>
    <option value="353434534">353434534</option>
    <option value="535443335, 756555666, 755444566">535443335, 756555666, 755444566</option>
    <option value="577543332">577543332</option>
    <option value="755444566">755444566</option>
 </select>

...but I want the output to be like this

<select name="CommitIDListID" class="btn btn-default dropdown-toggle" id="CommitIDListID" multiple="multiple">
    <option value="553564646">553564646</option>
    <option value="345456456">345456456</option>
    <option value="353434534">353434534</option>
    <option value="535443335">535443335</option>
    <option value="577543332">577543332</option>
    <option value="755444566">755444566</option>   // my data will be distinct because I have two records of the same commit ID
    <option value="756555666">756555666</option>
</select>

This is the code that I have right now:

<select multiple="multiple" id="CommitIDListID" name="CommitIDListID" class="btn btn-default dropdown-toggle">
                                @foreach (var data in Model.CommitIDList)
                                {
                                    if (data.Selected)
                                    {
                                        <option value="@data.Value" selected="selected">@data.Text</option>
                                    }
                                    else
                                    {
                                        <option value="@data.Value">@data.Text</option>
                                    }
                                }
                            </select>


  public IEnumerable<SelectListItem> GetAllCommitIDList()
        {
            var GetCommitID = _unitOfWorkCABusinessRules.RuleDetailRepo.GetAll().GroupBy(x => x.CommitID).Select(y => y.First()).Distinct();

            return GetCommitID
                 .Select(x => new SelectListItem
                 {
                     Text = x.CommitID,
                     Value = x.CommitID.ToString(),
                 })
                .Distinct()
                .OrderBy(x => x.Text);

}

This is the code that I'm working on; I know my syntax is wrong:

var CommitIDData = _unitOfWorkCABusinessRules.RuleDetailRepo.GetAll().Select(g => g.CommitID = string.Join(", ", g.CommitID)).Distinct();
         
   return CommitIDData 
                .Select(g => new SelectListItem
                {
                    Text = g.CommitID,
                    Value = g.CommitID.ToString(),
                })
                 .Distinct()
                .OrderBy(g => g.Text);

My table looks like this: table "RuleDetail"

RuleDetailId    Version         Environment     CQTicket        CommitID
16              Version33	    SIT	            ENT19293	    353434534
17              Version22	    SIT	            ENT95837	    345456456, 553564646
18              version 5	    SIT	            ENT8374	        535443335, 756555666, 755444566
19              version 10	    SIT	            ENT89484	    577543332
20              version25	    SIT	            CQ ticket 55	755444566
21              Version11	    SIT	            ENT00222222

Thank you so much for your help,