The correct answer is: A. Simply supported beam.
A simply supported beam is a beam that is supported at both ends. The ratio of the span to the overall depth is a measure of the stiffness of the beam. If the ratio does not exceed 10, the stiffness of the beam will ordinarily be satisfactory.
A continuous beam is a beam that is supported at more than two points. The stiffness of a continuous beam is greater than the stiffness of a simply supported beam.
A cantilever beam is a beam that is supported at one end and free at the other end. The stiffness of a cantilever beam is less than the stiffness of a simply supported beam.
Therefore, the stiffness of the beam will ordinarily be satisfactory in case of a simply supported beam.