Tensile strength of a material is defined as:

The tensile strength of a material is fundamentally about its ability to withstand deformation under tension. The choice stating that tensile strength is defined as the amount of load a material can withstand divided by its original cross-sectional area breaks this concept down into a measurable quantity. This definition illustrates that tensile strength is quantified by taking the maximum load applied to the material just before it fails and dividing that by the cross-sectional area over which that load is applied. This gives a clear representation of how much stress the material can endure while being stretched.

Understanding this definition helps clarify why the other options do not fully encapsulate tensile strength. While the resistance to being pulled apart captures the essence of tensile strength, it does not provide the necessary quantitative measure that is critical in engineering analysis. Similarly, the point at which a material begins to yield pertains more to the yield strength rather than tensile strength since it focuses on the onset of permanent deformation rather than the capability before breaking. Lastly, maximum stress without breaking, while closely related to tensile strength, does not account for the original cross-sectional area of the material, which is essential for calculating true tensile strength. Hence, the first choice accurately defines tensile strength in terms of its foundational parameters.