A certain life table has value = 0.1222 and +1 = 0.1384 . Actuary A calculates the value of +0.5 based on the UDD assumption resulting in a value of "a". Actuary B calculates the same probability based on the assumption of constant force of mortality in each integral year of age, resulting in a value of "b". What is the sum of a and b?

(a) 0.25 (b) 0.26 (c) 0.27 (d) 0.28 (e) 0.29