What carrying technique involves four providers and allows them to face forward while moving the patient?

The carrying technique that involves four providers and allows them to face forward while moving the patient is known as the diamond carry. This method is particularly effective for transporting a patient in a coordinated and safe manner. In a diamond carry, each provider grabs a corner of a stretcher or other support device, ensuring that the patient is securely supported. This configuration allows all four individuals to maintain good visibility of the surroundings, facilitating communication and coordination as they maneuver the patient through various environments.

In contrast, the other options do not pertain to patient transport techniques. "Bubonic plague" refers to a disease caused by a bacterial infection, not a method of carrying a patient. "Bulk storage containers" generally indicate storage equipment used for materials rather than methods employed in emergency medical situations. "Diaphoretic" describes a condition of excessive sweating, which also has no relation to carrying methods for patients. Thus, the diamond carry is the only relevant and applicable answer in this context.