An unwitting insider is best described as which of the following?

An unwitting insider is best characterized as someone who inadvertently discloses sensitive information to individuals who do not have a legitimate need to know, often due to a lack of awareness of the potential consequences of their actions. This type of individual typically has access to protected information but does not recognize the importance of maintaining its confidentiality or the potential risks involved in sharing it. The essence of being an unwitting insider lies in the unintentional nature of the information leak, highlighting the need for training and awareness to prevent such occurrences.

In contrast, the other choices focus on intentional actions, specific classifications, or security clearances which do not align with the concept of an unwitting insider. For example, a person sharing information maliciously or with intent does not fit the definition of "unwitting." Similarly, government officials with classified access operate under established security protocols, and contracted employees lacking a security clearance would not be in a position to unintentionally disclose classified information they do not have access to in the first place.