Not able to update custom field from Apex class, getting below error:

Illegal assignment from List to List<Rating_Request__c>

Can anyone help where I am doing wrong. If possible provide sample code.

Not able to update custom field from Apex class, getting below error:

Illegal assignment from List to List<Rating_Request__c>

Can anyone help where I am doing wrong. If possible provide sample code.

Below is my code :

public void updateflgusertb(string Selected)
{
    
    List<Rating_Request__c> usr = [SELECT ID,Question__c,Order_Sequence__c,User_Ratings__c FROM                     
        Rating_Request__c where User__c=:UserInfo.getUserId() and User_Rating__c = 0 
        group by                           
        ID,Question__c,Order_Sequence__c,User_Ratings__c 
        order by Order_Sequence__c  LIMIT 1];
    List<Rating_Request__c> rateupdate = new List<Rating_Request__c>();  
    for(Rating_Request__c objrating : usr)
    {
        objrating.User_Ratings__c = Selected;
        rateupdate.add(objrating);
    }
    update(rateupdate);
    
}

Thanks in advance