Identify the Letter of the Choice That Best Matches the Phrase

Identify the letter of the choice that best matches the phrase or definition.
a.screenshot
f.caption
b.index
g.field
c.reference
h.cross-reference
d.Top
i.switch
e.sidebar
j.gutter margin
-A text box that runs across the top or bottom of the page or along the edge of the right or left side of the page.