Seeds are produced______.

The correct option is C both by angiosperms and gymnosperms
Seeds are not produced by all plants. Seeds are produced only by gymnosperms and angiosperms. Hence these are called spermatophytes or seed plants. Seeds are the final products of sexual reproduction in spermatophytes. The gymnosperms produce naked seeds (seeds not enclosed within the fruit) and angiosperms produce seeds enclosed within the fruit.

Vascular plants include pteridophytes, gymnosperms and angiosperms.

Pteridophytes do not produce seeds.