Answer:
Double
Step-by-step explanation:
In a formal report, sometimes it is required to be double spaced. A report with double spacing will shows a space in between two typed lines. This space between the typed lines will enable a teacher or reviewer to write relevant comments or mark. A single-space report will leave no room for editing mark or giving comments at the precise location of the contents. As a general rule, we should format our report in double spaced unless we are explicitly told to use single spaces in formatting our report.