Final answer:
The B149.2 code is the one that applies to all appliance and piping installations downstream of the natural gas meter, focusing on propane storage and handling installations.
Step-by-step explanation:
The code that applies to all appliance and piping installations downstream of the natural gas meter is b) B149.2. The Canadian Standards Association (CSA) B149.2 Code is specific to the installation code for propane storage and handling. Whereas, CSA B149.1 covers natural gas and propane installation code, B149.3 covers the code for appliances and equipment, and B149.4 covers the code for digester gas. The B149.2 code is the one that applies to all appliance and piping installations downstream of the natural gas meter, focusing on propane storage and handling installations.