As your daughter bugs you to get a new phone you look into the cost of adding another line to your plan. The phone company offers three options for the same phone and plan with a different upfront payment and monthly cost as in the table below. The term of the plan is 2 years. Your personal interest rate which you use for calculations is 6% p.a. Plan option montly fee and upfront cost for the three options are:

-super tab Monthly fee 80 and upfront cost 30

- tab Monthly fee 70 upfront 210

- no tab mostly fee 60 upfront 420

What is the cheapest plan option?

Through your employer you will get a discount on the monthly fee but not on the one time cost. The person who knows the exact discount left the office early today. Which plan option will benefit the most from such a discount?