What type of evidence is classified as secondary?

Secondary evidence is classified as evidence that is not an original source but is instead used to support or substitute primary evidence when the latter is unavailable. This classification comes into play, especially in legal contexts, where primary evidence typically consists of original documents or direct testimony.

In this case, secondary evidence serves as a replacement option, meaning it provides indirect proof or corroboration of facts or information contained in primary evidence. For instance, if an original document is lost or cannot be produced, copies of that document or testimonies regarding its content may constitute secondary evidence.

The other options refer to different types of evidence. Direct testimony from an eyewitness falls under primary evidence as it comes directly from a person who witnessed an event. Original documents are the literal primary sources. Partial evidence of facts could imply incomplete or insubstantial information, which doesn't specifically classify as secondary evidence in the traditional sense. Therefore, the definition of secondary evidence aligns perfectly with the description provided in the correct choice, illustrating its role in legal contexts and evidentiary standards.