The 10.80% debentures of Toxic Chemical Corp. mature on December 1, 2031 and currently trade at 109.1. Interest is paid semi-annually and December 1 is a coupon anniversary date. [Assume today is December 1, 2020 so term to maturity is 11 years.] The debentures have a sinking fund requiring redemption of the debentures according to the schedule shown below. Selection of bonds to be redeemed is done by random draw, or lottery. Assume the issuer does not currently hold any bonds and will not acquire bonds other than to satisfy sinking fund requirements.

Years 1 - 6, 7, 8, 9, 10, 11

Sinking Fund None, 20% , 20%, 20% , 20%, 20%

22. With coupons paid semi-annually, the Convexity of the debentures is:

1. 23.1
2. 40.5
3. 44.2
4. 48.4
5. 52.9