The correct answer is Stupa.
A Stupa is a mound-like structure containing Buddhist relics, typically the ashes of Buddhist monks or nuns, used as a place of meditation and veneration in Buddhism. However, some Jain temples have also built stupas as they are considered sacred to both religions. The other options are not associated with either Buddhism or Jainism. The Pyramid is associated with ancient Egyptian religion, the Longhouse is a type of traditional housing used by Native American tribes, and the Ziggurat is a type of ancient Mesopotamian temple.