Three corporations x y z have preferred stock the current

Question

Three corporations (X, Y, Z) have preferred stock. The current stock price per share and dividend per share of the preferred stock of X, Y, and Z are shown below.

X: stock price = $50, dividend per share = $3

Y: stock price = $60, dividend per share = $4 

Z: stock price = $80, dividend per share = $4

If you calculate the cost of the preferred cost stock (R_P) for each and list these in order from HIGHEST R_P to LOWEST R_P, the correct order is _____.