The correct option is C they have no ovary
Seeds are found both in gymnosperms and angiosperms.
The seeds and fruits are the results of pollnation and fertilization in plants. The ovary in angiosperms develops into the fruit whereas the ovules become the seeds enclosed within the fruit.
Gymnosperms (meaning 'naked seeds') are plants whose ovules are exposed as it does not have an ovary wall and hence the seeds that develop post-fertilisation are not covered. The ovular integuments form the seed coat.