12. The spot price of god is $400/oz. The 1-year, 2-year, and 3 -year god forward prices are $410/oz,$434/oz, and $455/oz, respectively. Interest rates are r(0,1)=5.5%,r(0,2)=6.0%,r(0,3)=6.25%. What is the annual coupon of the 3-year gold-linked note that sells at par? This note pays the cash coupon at the end of each year. (Use the continuous compounding.)