Final answer:
The primary function of the Lukasa in Luba culture is to act as a mnemonic device used by memory men or masters of the Mbudye society to record and recall cultural knowledge, historical narratives, and genealogy.
Step-by-step explanation:
The Lukasa is a memory board that is a significant part of the Luba culture. While none of the provided options directly describe the function of the Lukasa, it is closely related to the first option related to divination. The Lukasa is used as a mnemonic device to record and interpret historical narratives, genealogy, and maps of sacred landscapes. The Luba people's holders of history and knowledge, known as the memory men or masters of the Mbudye society, use these hand-held wooden boards which are studded with beads and metal to recall and narrate stories, songs, and proverbs. These narratives often serve to legitimize leadership and policy decisions within the culture. The role of the Lukasa is, therefore, primarily associated with the preservation, display, and interpretation of cultural knowledge rather than for divination, decoration, weaponry, or cooking.