The correct answer is A. Horizontal files.
Horizontal files are also known as flat files or tray files. They are designed to lie flat horizontally in a cabinet. They are typically made of cardboard or plastic and have a series of drawers or trays that can be used to store documents. Horizontal files are often used in offices and other settings where space is limited.
Vertical files, on the other hand, are designed to stand upright in a cabinet. They are typically made of metal or wood and have a series of slots or pockets that can be used to store documents. Vertical files are often used in libraries and other settings where space is not as limited.
Visible files are a type of file that is designed to be easily seen. They are typically made of clear plastic or glass and have a front panel that allows you to see the contents of the file without having to open it. Visible files are often used in retail settings where customers need to be able to see the products that are available.
Metal files are a type of file that is made of metal. They are typically used to store important documents or files that need to be protected from damage. Metal files are often used in businesses and other settings where security is a concern.