Correct option (b) basal
Explanation:
In basal placentation, ovary is bicarpellary, syncarpous and unilocular and a single ovule is borne at the base of ovary, e.g. marigold.
In marginal placentation, the ovary is simple, unilocular and the ovles are arranged along the margin of the unilocular ovary, e.g. pea.
In free central placentation, ovary is unilocular and the placenta bearing ovules arise from the central axis, e.g. Stellaria.
In axile placentation, ovary is two or more chambered, usually as many as the number of carpels, e.g. Petunia.
