6-A large public company has a beta of 1.45, a debt ratio of 35% and a tax rate of 36%. A similar private company has a debt ratio of 40% and tax rate of 32%. What is the beta of the private company?

a) 1.21

b) 1.35

c) 1.42

d) 1.57

e) 1.69

NEED to see the work and formulas PLZ. Will rate! :)