How to call other constructors from a constructor in c#?

Question

I have a constructor like:

public Blah(string a, string b)
{

}

public Blah(string a, string b, string c)
{
  this.a =a;
  this.b =b;
  this.c =c;
}

How can I call the 2nd constructor from the 1st one?

like:

public Blah(string a, string b)
{
   Blah(a,b, "");
}

Answer 1

public Blah(string a, string b) : this(a, b, "")
{
}

public Blah(string a, string b, string c)
{
    // etc
}