The correct options are
A Reduction of AuCl3
D Bredig's are method
Colloidal gold is a suspension (or colloid) of sub-micrometer size particles of gold in a fluid usually water.
Generally, gold nano-particles are produced in a liquid (liquid chemical methods) by reduction of chloro-auric acid (H[AuCl4]).
The other methods of preparation are as follows:
1) Turkevich method
2) Bredig's are method
3) Brust method
4) Perrault method
5) Martin method.