It is necessary to 'chalk' a file when the metal you are filing is __________.

Correct Answer: Option A — aluminum

Chalking a file prevents aluminum, a soft and ductile metal, from clogging the teeth (pinning). The chalk acts as a lubricant and filler, allowing the file to cut efficiently without tearing the material surface. This technique is standard practice when working with non-ferrous, gummy metals in shipboard workshops.