What type of shell instrument is prepared by cutting a hole and blown like a trumpet?

The conch is a shell instrument that is made by cutting a hole at the end of a conch shell, which allows it to be blown similar to a trumpet. This traditional instrument has been used in various cultures for centuries, often in ceremonial contexts or as a signaling device. Its unique shape and sound production method differentiate it from other wind instruments, making it a fascinating example of how natural materials can be transformed into musical instruments.

While other options like the ocarina are also wind instruments, they are typically made from clay or other materials and are not shell-based. The siku and zampoñas are types of pan flutes originating from South America and consist of multiple pipes rather than being derived from a single shell. Thus, the specific characteristics and method of playing the conch make it the correct answer to the question.