The formula for the cost per equivalent unit using the weighted$-$average method is Blank$\_\_\_\_\_\_.$ Multiple choice question. $($Cost of beginning work in process inventory $-$ Cost added during the period$)-$: Equivalent units of production $($Cost of beginning work in process inventory $+$ Cost added during the period$)-$: Equivalent units of production $($Cost of ending work in process inventory $+$ Cost added during the period$)-$: Units produced $($Cost of ending work in process inventory $+$ Cost added during the period$)-$: Equivalents units of production