The sexual reproductive organs of aspergillus are antheridium and ascogonium. Antheridium is the male reproductive structure, which produces spermatia. Spermatia are small, non-motile cells that are involved in the process of fertilization. Ascogonium, on the other hand, is the female reproductive structure, which receives the spermatia and undergoes fertilization to form a zygote. In aspergillus, the process of sexual reproduction involves the fusion of the ascogonium and the antheridium, resulting in the formation of a zygote. This zygote then undergoes further development to form a structure called an ascus, which contains the spores of the fungus. Therefore, option 4 is the correct answer.

Note: In some species of aspergillus, the sexual reproductive organs and structures may vary, so it is important to consider the specific species when studying its sexual reproduction.