Select the most appropriate option to fill in the blank.

She smashed a ______ of glass with the metal vase.

pane

The most appropriate option to fill in the blank is pane.

The sentence is about how she smashed a pane of glass with the metal vase. The word "pane" refers to a single sheet of glass, typically in a window. This is the most appropriate word because it accurately describes what was broken.

The other options are not as appropriate.

• Pion is a chess piece. This does not make sense in the context of the sentence, because a chess piece cannot be broken with a metal vase.
• Pawn is a chess piece. This does not make sense in the context of the sentence, because a chess piece cannot be broken with a metal vase.
• Pain is a feeling of physical or emotional suffering. This does not make sense in the context of the sentence, because the speaker is not talking about pain, they are talking about a pane of glass.