Final answer:
Ink chromatography is the test used to determine which pen was used for a note by separating and comparing the ink's components.
Step-by-step explanation:
To determine which pen was used for a note, the appropriate test is ink chromatography. This analytical method separates the components of the ink used on the document, allowing forensic scientists to compare the ink from the note with samples from different pens. Ink chromatography is an essential tool in forensic science for the examination of documents.
Unlike DNA analysis, which analyzes biological samples such as hair, semen, saliva, and blood, or handwriting analysis, which focuses on comparing the stylistic features of a person's writing, ink chromatography specifically targets the chemical composition of the ink used.