C# String ToUpper()

public string ToUpper()
public string ToUpper(CultureInfo)

    using System; 
            
    public class StringExample  
    {  
        public static void Main(string[] args)  
        {  
           string s1 = "Hello C#";
           string s3 = s1.ToUpper();
           Console.WriteLine(s3);
        }  
    }  

HELLO C#