Only genuine expert plz $??$ When designing a reinforced concrete beam subjected to bending, what is the primary function of the longitudinal reinforcement, commonly known as rebars?

a$)$ Longitudinal reinforcement primarily provides resistance against shear forces acting on the beam, preventing sudden failure and ensuring structural stability.

b$)$ The main function of longitudinal reinforcement is to control cracking and enhance the ductility of the beam, allowing it to deform plastically before ultimate failure occurs.

c$)$ Longitudinal reinforcement serves to increase the compressive strength of the concrete, reducing the likelihood of buckling and ensuring adequate load$-$carrying capacity.

d$)$ The primary role of longitudinal reinforcement is to provide tensile strength to the concrete beam, counteracting the tensile stresses induced by bending loads and preventing brittle failure.