The correct option is D Oblique ovary
The genus Datura with its nine species are a group of poisonous plants, especially their seeds and flowers. Being herbaceous leafy annuals and short-lived perennials, their fruit are spiny capsule that splits open when mature to release numerous seeds. This plant is placed under the family Solanaceae because it shows the characteristics of a the family with a solitary flower with five fused sepals and petals, superior ovary with two fused carpels and obliquely placed in the flower.
Thus, the correct answer is option D.