Which of the following is an invisible item?

The invisible item in the list is "Banking services". In economics, visible items are tangible goods that can be physically seen and touched, while invisible items are intangible services that cannot be physically seen or touched. Petroleum services, processed rice, and processed milk are all visible items because they are tangible goods that can be seen, touched, and measured. On the other hand, banking services are intangible and cannot be physically seen or touched. Examples of banking services include providing loans, managing savings accounts, facilitating transactions, and offering financial advice. Therefore, banking services are considered an invisible item because they are intangible and cannot be physically seen or touched.