$1($o$).$ Compute the number of units avallable for sale in March.

$1($b$).$ Compute the number of units in ending inventory on March $31.$

$2.$ Compute the cost assigned to ending inventory using specific identification. Note. The March $9$ sale consists af $80$ units from March $1$ purchase and $340$ units from the March $5$ purchase; the March $29$ sale consists of $40$ units from the March $18$ purchase and $120$ units from the March $25$ purchase.