The correct choice is (b) In parietal placentation, placenta is swollen at centre and ovules get arranged around it
Easiest explanation: In basal placentation, ovule is present at base of the ovary. In free central placentation, placenta is swollen at the centre and ovules get arranged around it. In apical placentation, ovule is present at apex of the ovary. Lemon is an example of axial placentation.