The correct answer is: A. Minimum dimension
The throat of a weld is the minimum dimension of the weld cross-section perpendicular to the direction of loading. It is the effective area of the weld that resists the applied load.
The average dimension of the weld cross-section is not a meaningful measure of the weld’s strength, as it includes areas of the weld that are not contributing to load resistance. The maximum dimension of the weld cross-section is also not a meaningful measure of the weld’s strength, as it includes areas of the weld that are not in direct contact with the load-bearing member.
The throat of the weld is the only dimension that is directly related to the weld’s strength. It is therefore the most important dimension to consider when evaluating the strength of a weld.