C# Object Array Changing all element properties [closed]

Question

Just started learning C# and struggling to understand what is happening. Here is a simplified version of my problem.

I have two classes called Dog and Kennel. Kennel houses a 2D array of type Dog. Dog has multiple properties (breed, color), but just _name is all we need for this example.

I want to change the name of a single dog. I tried:

kennel.Dogs[4,4].Name = "Fido"

but it sets ALL the dogs to the name of "Fido". Not just the dog at (4, 4). Why?

Example:

using System;
                    
public class Program
{
    public static void Main()
    {
        Console.WriteLine("Hello World");
        Kennel kennel = new Kennel();
        
        kennel.Dogs[4,4].Name = "Fido";
        Console.WriteLine(kennel.Dogs[4,4].Name); //Expectation: Fido; Result: Fido
        Console.WriteLine(kennel.Dogs[2,2].Name); //Expectation: Bowser; Result: Fido
    }
}

class Kennel {
    public Kennel() {
        this._dogs = new Dog[10,10];
        for (int i = 0; i < 10; i++)
        {
           for (int j = 0; j < 10; j++) {
               _dogs[i, j] = defaultDog;
               defaultDog.Name = "Bowser";
           }
        }
    }
    private string _name;
    private Dog defaultDog = new Dog();
    private Dog[,] _dogs;

    public string Name
    {
        get { return _name; }
        set { _name = value; }
    }
    public Dog[,] Dogs
    {
        get { return _dogs; }
        set { _dogs = value; }
    }
}
class Dog {
    private string _name;

    public string Name
    {
        get { return _name; }
        set { _name = value; }
    }
}