The correct option is D Testis matures earlier than ovary
Cross fertilisation occurs in Hydra. The testis matures earlier than ovary. The spermatozoa released from the testis of one Hydra swim in water with their tails and finally come into contact with the ovum of another. Hydra. Ovum lives only for a short time after it is exposed. During this period, fertilisation must take place. Thus, given figure is not showing self-fertilisation but cross-fertilisation.