Constructors - General Questions

If a class defines a constructor with parameters only, does C# still provide a default parameterless constructor?

What is the output of the following program?

Console.WriteLine(new P().V);
class P {
    public int V;
    public P() : this(7) { }
    public P(int v) { V = v; }
}

What is a static constructor used for?

What is the output of the following program?

var r = new Rect(4);
Console.WriteLine(r.Area);
class Rect
{
    public int W, H;
    public Rect(int s) : this(s, s) { }
    public Rect(int w, int h) { W = w; H = h; }
    public int Area => W * H;
}

What is the output of the following program?

var a = new A();
class A
{
    public A() { Console.Write("ctor"); }
}