How is the pressurization system manually controlled?

The pressurization system of the A320 can be manually controlled by selecting the MODE SEL Switch to the MAN position. This action signifies that the crew will take manual control of the system, enabling them to manage the outflow valve directly. By then using the MAN V/S CTL Switch, the crew can effectively control the rate at which the cabin pressure changes, allowing for precise adjustments as required, particularly in situations where automatic control may not be suitable.

The focus here is on the ability to manage the outflow valve, which is critical in maintaining proper cabin pressure during various phases of flight such as climb and descent. This is essential when operating under specific conditions or when the automated systems may not respond adequately.

The other choices do not fully enable the manual control of the pressurization system in the same manner, as they either concentrate on the landing elevation selector or do not incorporate both necessary components for effective manual operation.