What types of areas does CAP primarily support with its water supply?

The Central Arizona Project (CAP) primarily serves urban and suburban areas with its water supply. The CAP is a critical infrastructure project that delivers Colorado River water to various parts of Arizona, primarily supporting cities and towns in metropolitan areas such as Phoenix and Tucson. This supply is vital for residential needs, landscaping, and commercial development in urban settings.

While agricultural regions do receive some water from CAP, the primary focus has been on meeting the demands of growing urban populations. Urban and suburban areas require substantial amounts of water to support their larger populations and infrastructure, which is why the CAP's main efforts have been directed toward these regions.

Coastal and lakeside communities are not relevant in the context of CAP since Arizona is a landlocked state, and this project does not serve such areas. The emphasis on urban support reflects the ongoing development and population growth in those regions, making it the correct answer.