I buy a 12-year coupon bond that pays 5% coupon annually. The yield to maturity is 6% per year and Face Value of $100. There is another bond trading in the market. It is a 7-year bond paying a 6% annual coupon with a yield to maturity of 5% and Face Value of $100. Hedge your 12-year position using this bond. How many units of the second bond should you buy/sell?

a. sell 1.3215

b. buy 1.2293

c. buy 1.3215

d. sell 1.2293