Why can a rigid diaphragm assumption understate chord collector tension in flexible timber diaphragms?

Choices

• (A) Flexible sheathing lets shear redistribution drive larger chord truss effects at chord lines
• (B) Timber always exceeds concrete shear stiffness arbitrarily
• (C) Chord forces vanish whenever nails are overdriven slightly
• (D) Chord collectors ignore compatibility with perpendicular walls entirely