Answer:
a.the FIFO method
Explanation:
FIFO which is First-In, First-Out can be defined as the method which are used for the purpose of cost flow assumption in the cost of goods sold calculation because the FIFO method tend to assumes that the products that are oldest in a company's inventory have been sold first and that the costs which are paid for those oldest products are the ones used in the calculation which is why FIFO said to be an asset-management as well as valuation method because assets that are produced or acquired first are sold or used first.
Therefore based on the above given details the inventory method which results in the highest gross profit for June will be the FIFO method.
