ANS:B - maximum bending moment

The amount of reinforcement for main bars in a slab is typically based on the maximum bending moment experienced by the slab. Main reinforcement bars in a slab are primarily designed to resist bending moments. The maximum bending moment occurs at critical sections of the slab, such as the mid-span or support regions. Therefore, the reinforcement detailing and quantity are determined based on the maximum bending moment to ensure that the slab can safely resist bending stresses without experiencing excessive deflection or failure. Hence, the correct answer is:

• Maximum bending moment