Explanation:

- Harmika: This is a small platform with a railing located at the top of a stupa, representing a sacred space.

- Gopura: Typically associated with South Indian temples, these are monumental entrance gateways and not part of traditional Buddhist stupas.

- Gopura is the correct answer.

- Chhatra: This is an umbrella-like structure symbolizing high rank and protection, often placed atop the harmika.

- Anda: This is the dome or egg-shaped structure, representing the mound of relics and the universe.