Designer: Any garden and adjoining living room that are separated from one another by sliding glass doors can visually merge into a single space. If the sliding doors are open, as may happen in summer, this effect will be created if it does not already exist and intensified if it does. The effect remains quite strong during colder months if the garden is well coordinated with the room and contributes strong visual interest of its own. The designer's statements, if true, most strongly support which one of the following? ['A garden separated from an adjoining living room by closed sliding glass doors cannot be well coordinated with the room unless the garden contributes strong visual interest.', 'A garden and an adjoining living room separated by sliding glass doors cannot visually merge in summer unless the doors are open.', 'Except in summer, opening the sliding glass doors that separate a garden from an adjoining living room does not intensify the effect of the garden and room visually merging into a single space.', 'A garden can visually merge with an adjoining living room into a single space even if the garden does not contribute strong visual interest of its own.']