Which of the following organism has 12 number of chromosomes in meiocytes?

House fly.

The correct answer is Option (2) -House fly.

Rice: Rice (Oryza sativa) typically has 24 chromosomes in its diploid cells (2n = 24). Therefore, its meiocytes (which are diploid) would have 24 chromosomes.

House fly: The house fly (Musca domestica) has 12 chromosomes in its diploid cells (2n = 12). This means its meiocytes also have 12 chromosomes.

Fruit fly: The fruit fly (Drosophila melanogaster) has 8 chromosomes in its diploid cells (2n = 8).

Human beings: Humans have 46 chromosomes in their diploid cells (2n = 46).

Thus, the organism with 12 chromosomes in its meiocytes is the house fly.