Which of the following is NOT a method of reproduction in animals?

Sporulation is reproduction by making spores. It is used by fungi (like mushrooms and bread mould), many bacteria, some algae and ferns — not by animals. That is why it is the odd one out here.

The other choices are all real animal methods. Sexual reproduction (male gamete joining female gamete) is the common one in animals. Asexual reproduction happens in simple animals where one parent makes offspring without gametes. Budding is one type of asexual reproduction and is seen clearly in Hydra, where a small bud grows on the parent’s body then breaks off as a new animal.

So the method that belongs to plants, fungi and microbes rather than animals is sporulation.