Manganese can result in which of the following?

Manganese is known to cause black stains on plumbing fixtures and other surfaces. This discoloration occurs because manganese can precipitate out of water, particularly when it is in high concentrations. When water containing manganese comes into contact with fixtures or surfaces, it can leave behind these unsightly black residues that can be challenging to remove.

In contrast, rusty pipes are typically associated with iron and corrosion, while odors in water are often linked to organic matter or other contaminants, not specifically manganese. Corroded fittings are usually a result of acidic water or other forms of corrosion, which would not directly relate to manganese levels. Thus, the presence of manganese is distinctly recognized for causing black stains, making it the clear focus of this question.