Final answer:
Optional detachment of reporting senior reports for E1-E6 are submitted as C4 reports, documenting significant performances in temporary duties.
Step-by-step explanation:
Detachment of reporting senior reports for E1-E6 that are considered optional are submitted as C4 reports. These reports may be submitted to document significant performance in duties of a temporary additional duty or a temporary duty under instruction status that is not going to be reported in a regular report. This kind of report depicts an individual's performance during a specific period of detachment and it is at the discretion of the reporting senior to submit a C4 report if deemed necessary.