6. (150-83-99 #4) Z is the present-value random variable for a special insurance on (x). You are given: (i) There are three causes of decrement. (ii) 6 = 0.04. (iii) AT (t) = 0.005, t 2 0. (iv) My (t) = 0.010, t20. (v) (t) = 0.020, t 2 0. (vi) Butt = 3, Osts10; [2, Osts 20; (3) = 1, t20. 0 , (vii) Butt (viii) Bitt t > 10. O, t > 20. (ix) Benefits are payable at the moment of decrement. Calculate Var(Z)