Opentech Corporation recently paid a cash dividend of $2.20. Their dividend 12 years ago was $1.30. Currently, their common stock price is $50 per share. If they issue new shares, they will pay flotation costs of $2 per share to the investment bankers. Their corporate tax rate is 21%. What is the firm's cost of external equity?

a) 9.21%

b) 9.10%

c) 8.90%

d) 9.27%

e) 9.93%