Utilize the input text as a context reference, choose the right relationship between South32 and manganese from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

One issue that has clouded the perceptions of South32 is the prospect of write downs in the fair value of its Australian and South African manganese operations.

Answer: product_or_material_produced