Asexual reproductive structures of sponges are

Gemmules

The correct answer is Option (2) → Gemmules

Reproduction in fungi can take place by vegetative means – fragmentation, fission and budding. Asexual reproduction is by spores called conidia or sporangiospores or zoospores, and sexual reproduction is by oospores, ascospores and basidiospores. The various spores are produced in distinct structures called fruiting bodies.

Members of the Kingdom Fungi and simple plants such as algae reproduce through special asexual reproductive structures. The most common of these structures are zoospores that usually are microscopic motile structures. Other common asexual reproductive structures are conidia (Penicillium), buds (Hydra) and gemmules (sponge).

Gemmules are internal buds found in sponges and are involved in asexual reproduction . It is an asexually reproduced mass of cells, that is capable of developing into a new organism i.e., an adult sponge.