In civil engineering, how do prefabrication and modular construction methods contribute to streamlining the construction process and reducing project timelines?

A$)$ By enabling simultaneous on$-$site and off$-$site construction, accelerating project completion.

B$)$ By requiring extensive on$-$site labor, thereby increasing project timelines.

C$)$ By solely relying on traditional construction methods, prolonging project durations.

D$)$ By disregarding efficiency and cost$-$effectiveness in construction planning