Which of the following features is common to all Marriott properties regardless of the brand?

High-speed internet access is a feature that is consistent across all Marriott properties, regardless of their specific brand. This commitment to connectivity caters to the diverse needs of guests, who may include business travelers requiring reliable internet for work, as well as leisure travelers wanting to stay connected with friends and family. By standardizing high-speed internet access, Marriott ensures a baseline level of service that enhances the guest experience, promotes customer loyalty, and meets the expectations of modern travelers.

In contrast, unique architectural designs can vary greatly between brands and locations, reflecting local cultures and the distinctiveness of each property. Outdoor pools are not present at every Marriott property, especially in urban environments where space is limited. Free room upgrades are typically subject to availability and may depend on the specific hotel’s policies or the guest's loyalty status, making this option inconsistent across the brand.