GTK+ Licensing query

[sushil <skdeka gmail com>]

Hi,
  I am new to Linux development and would like to develop a GUI using
gtk+. The following are my queries

1. Can I write a close source software using GTK+?
2. Do I need my source code to be  licensed under GNU LGPL 2.1?
3. I would like to use dbus libs along with GTK+. Is it pissible under
the same license.
4. Is it possible to run the application on KDE desktop also?

I am sorry, if I asked any funny questions.

Thanks & regards,
Sushil k Deka