here is the question please solve correctly

Many telecommunication companies package a new phone along with their mobile data plan. Suppose one company sends the promotion in Figure 1 to full time university students: They also advertise that Bond University students receive a bonus offer where, if they sign up now, they receive the first 4 months free of charge. a. Find a function to describe the total cost of this new phone and mobile plan for Bond University students. (3 marks) b. Determine the total cost to join this plan for 4 years. (2 marks) c. Find a function to describe the average monthly cost. (3 marks) d. Graph the function described in part (c). Interpret the values of interest. (5 marks) e. The official selling price of the phone is $599. The same mobile plan for non-Bond University students costs $30 per month. Which way is the cheapest to get the phone and use the mobile service? Explain your