Why do long industrial roofs with structural steel skeletons routinely insert expansion/movement joints?

Choices

• (A) Cumulative axial growth from ΔT threatens secondary members and cladding joints
• (B) Steel coefficients of thermal expansion are negligible beyond 30 m bays
• (C) Movement joints abolish diaphragm shear transfer permanently
• (D) Roofs are detailed monolithic to foundations without slip