explain it

9. Which component of a firm's capital structure is the most difficult to estimate? O A. Private placements of debt O B. Bond-financed debt O C. Preferred stock O D. Equity O E. Bank loans 10. Donnelly and Son pay $8 as the annual dividend on their preferred stock. Currently, this stock is seling for $72 a share. What is Donnelly's cost of proferred stock? O A. 11.11 percent 0 B. 9.72 percent O c. 7.78 percent O D. 11.99 percent O E. 9.00 percent