What is the web address where the EGDM can be accessed?

The web address where the EGDM (Environmental General De-Icing Manual) can be accessed is indeed https://regionaltraining.aa.com. This website is specifically designed to provide training resources and manuals related to de-icing and other aviation-related topics, making it the correct source to find the EGDM.

The other options may represent legitimate websites but do not specifically cater to the EGDM or related de-icing training materials. For instance, the FAA site provides regulatory information and safety guidelines, while aircraftmaintenance.com and deicingprotocols.com may not host the EGDM or may not be focused on training resources from American Airlines, which is where the correct link points. Therefore, the specific focus and intended use of the correct web address make it the most appropriate choice for accessing the EGDM.