Since there are no parameters given for temporary or contract workers, the assumption is that everyone that is hired or fired is a regular worker.
The chase plan involves a lot of hiring and firing as it targets the monthly demand irrespective of the hiring firing cost. This way, the inventory and backlog cost is minimized but the impact is seen due to hiring and firing.
Also the Level plan takes into consideration the entire demand is uniform. For this reason the entire demand is added and divided by 12 for even distribution. However this gives rise to inventory storage cost and at some points backlog cost. The monthly production target here is 328334. However to round up and close the year with 100,000 inventory, the last month production is 328326.
The images are attached with the tables.
Chase plan and level plan respectively