Text stimulus (diagram): Exterior building diagram. Shown: front entrance on left labeled 'Front office' with stairs. Shown: side entrance on right with ramp and locked door, no doorbell, no intercom, and no sign. Note: near side entrance reading 'Call office to unlock' but no phone number displayed. A building redesign created a side accessible entrance, but visitors must call the front office to unlock it; there is no doorbell, intercom, or sign at the side entrance. Which barrier is most direct?