The correct answer is A) smaller GM. The term "tender" refers to a vessel's stability characteristics. A vessel with a smaller metacentric height (GM) is considered more "tender" or less stable than a vessel with a larger GM. This is because a smaller GM results in a smaller righting arm (GZ) and a smaller range of stability, making the vessel more likely to heel over and be less responsive to correcting forces. The other options are incorrect because they do not directly relate to a vessel being more tender. A lower KG would actually make the vessel more stable, a smaller roll angle is a consequence of being more tender, and a larger GZ is indicative of a more stable vessel, not a more tender one.