Isra is analyzing the properties of several samples of elements to find out which sample is a metalloid. Which set of properties most likely belongs only to a metalloid?

Metalloids often have a shiny, high-luster appearance like metals, but are brittle like nonmetals. A high luster combined with brittleness is therefore the best match. Basic compounds are more typical of metals, while acidic compounds are more typical of nonmetals; being a gas also does not fit the usual properties of metalloids.

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