please explain step by step

For each of the following four independent scenarios, determine the information requested.

A$.$ In the beginning inventory, $5,000$ units were $40$ percent complete with respect to materials. During the period, $40,000$ units were transferred out. Ending inventory consisted of $7,000$ units that were $70$ percent complete with respect to materials. How many units were started and completed during the period?

B$.$ At the start of the period, $4,000$ units were in the work$-$in$-$process inventory; $3,000$ units were in the ending inventory. During the period, $9,500$ units were transferred out to the next department. Materials and conversion costs are added evenly throughout the production process. FIFO costing is used. How many units were started during the period?

C$.$ Beginning inventory amounted to $1,000$ units. This period, $4,500$ units were started and completed. At the end of the period, the $3,000$ units in inventory were $30$ percent complete. Using FIFO costing, the equivalent production for the period was $5,600$ units. What was the percentage of completion of the beginning inventory?

D$.$ The ending inventory included $$87,000$ for conversion costs. During the period, $42,000$ equivalent units were required to complete the beginning inventory, and $60,000$ units were started and completed. The ending inventory represented $10,000$ equivalent units of work this period. FIFO costing is used. What were the total conversion costs $(())$