Ovules occur along the ventral suture over a ridge in two rows in _______ placentation.
Placentation is the arrangement of the ovules on the placenta in the ovary. This arrangement can be of different types. In marginal placentation, the gynoecium is monocarpellary and apocarpous. The ovules are borne on the placentae that are present on the ventral suture forming a ridge. It is the margin of the ovary wall. This type of placentation is seen in Leguminosae family. Hence, the correct answer is 'Marginal'.