A _________ door consists of a mild steel frame. A. Louvered

a-door-consists-of-a-mild-steel-frame-a-louvered

A _________ door consists of a mild steel frame.

A. Louvered

B. Swing

C. Collapsible

D. Revolving

The question was posed to me during an interview.

This question is from Parts of Window topic in portion Doors, Windows and Ventilators of Construction & Building Materials

Correct choice is C. Collapsible

Easiest explanation: In Collapsible steel door, the two vertical pieces of mild steel channels, about 15 mm to 20 mm wide, are joined together with the hollow portion of the channel inside. A vertical gap of about 12 mm to 15 mm is thus created.