Answer: [A]: "bromine (Br)" .
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Note: "bromine" (Br) ; "chlorine" (Cl) ; and "fluorine" belong in the "halogen" family.
___________________________________________________Refer to the Period Table of Elements (shown below).
The vertical "columns" are referred to as: "groups"; or, "families". Refer to the "halogens"; or "halogen family" — circled in "black-color"; as follows:___________________________________________________