The correct answer is: A. Flexural tensile strength.
Modulus of rupture is a measure of the ability of a material to resist bending. It is calculated by dividing the load at failure by the area of the beam cross-section. The modulus of rupture is a useful property for designing concrete beams, as it allows engineers to estimate the maximum load that a beam can safely support.
Flexural tensile strength is the ability of a material to resist tensile stresses that are applied perpendicular to the direction of the material’s fibers. It is measured by the force required to break a beam of material that is loaded in bending. The flexural tensile strength of concrete is typically much lower than its compressive strength, which means that concrete beams are more likely to fail in bending than in compression.
Direct tensile strength is the ability of a material to resist tensile stresses that are applied parallel to the direction of the material’s fibers. It is measured by the force required to break a specimen of material that is loaded in tension. The direct tensile strength of concrete is typically much lower than its compressive strength or flexural tensile strength.
Split tensile strength is the ability of a material to resist tensile stresses that are applied perpendicular to the direction of the material’s fibers. It is measured by the force required to split a specimen of material in two. The split tensile strength of concrete is typically lower than its direct tensile strength.