ANS:A - Steel

Among the options provided, steel would generally be considered the most elastic material. Elasticity refers to the ability of a material to deform under stress and return to its original shape once the stress is removed. In the context of materials science, elasticity often refers to the material's ability to undergo reversible deformation without permanent damage. Steel is known for its high elasticity compared to the other materials listed. It can undergo substantial deformation under load and return to its original shape when the load is removed, provided the stress does not exceed its elastic limit. Rubber is indeed highly elastic, but its elasticity is usually associated with large deformations compared to steel. Rubber materials can exhibit significant stretch under stress and return to their original shape, but they may not be as suitable for applications requiring high strength and stiffness. Glass is a brittle material and typically does not exhibit significant elasticity. It tends to fracture rather than deform under stress, making it less elastic than steel. Brass, while it can deform elastically, is generally not as elastic as steel. It is often used in applications where corrosion resistance and machinability are more important than elasticity. Therefore, among the options provided, steel is the most elastic material.