2. MC also considers selling a high-end and a low-end model, 100 and 500 units per month, respectively. Their unit cost is $2000 and $500, respectively. The joint order cost is increased by $1000 for each additional product type (i.e., $7000 for three product types). Find the optimal number of joint orders per year and subsequently the optimal order quantity for each product type (round it to the nearest integer). Also, calculate the total annual cost for the three product types with joint orders.