Adamson Corporation is considering four average$-$risk projects with the following costs and rates of return:

structure consists of $75\%$ common stock, $15\%$ debt, and $10\%$ preferred stock.

a$.$ What is the cost of each of the capital components? Round your answers to two decimal places. Do not round your intermediate calculations.

Cost of debt $,\%$

Cost of preferred stock $,\%$

Cost of retained earnings $,\%$

b$.$ What is Adamson's WACC? Round your answer to two decimal places. Do not round your intermediate calculations.

$\%$

c$.$ Only projects with expected returns that exceed WACC will be accepted. Which projects should Adamson accept?

Project $1$

Project $2$

Project $3$

Project $4$