Types of reference source include one of the following

### Why this is right Sources can be classified by how directly they provide information about an event, subject, or finding. **Primary** sources provide original, firsthand material, while **secondary** sources discuss or interpret that material, so “primary and secondary” is the suitable pair. ### The concept A **primary source** is original evidence, such as a diary written at the time, an interview, or a research report presenting new results. A **secondary source** explains, evaluates, or summarizes information from primary sources, such as a history book discussing diaries and official records. These labels describe a source’s relationship to the information, not whether it is printed or online. Some classifications also include **tertiary sources**, which collect and summarize information from primary and secondary sources, such as encyclopedias. | Classification | What it describes | Example | |---|---|---| | Primary / secondary | How directly the source provides original evidence or interprets it | Original research report / review article | | Physical / virtual | The format or way the source is accessed | Printed book / online database | ### The other options - **A. Learned and unlearned**: These are not standard categories for classifying information sources. “Learned” might describe a person’s knowledge, which makes the wording tempting, but it does not identify a source’s role. - **B. Physical and virtual**: This describes a source’s format or access method, such as a printed book or a digital webpage. It does not distinguish original evidence from interpretation. - **D. Educational and academics**: These are not a standard pair of source types. They relate broadly to learning and academic settings, rather than how a source relates to its information. ### Terms - **Primary source**: Original material that provides direct evidence about a subject or event. - **Secondary source**: Material that analyzes, interprets, or summarizes primary sources. - **Tertiary source**: A work that gathers and condenses information from primary and secondary sources. - **Reference source**: A resource designed to help users find or check information, such as a dictionary or encyclopedia. ### Remember Primary sources provide original evidence; secondary sources explain or analyze that evidence.