Which of the following statements is correct?

A. A stock that sells for less than its book value is undervalued;

B. If a company's return on equity drops by half, the price/book value ratio will drop by more than half;

C. A combination of a low price/book value ratio and a negative return on equity suggests that a stock is undervalued;

D. Other things remaining equal, a higher growth stock will have a higher price/book value ratio than a lower growth stock;

E. In the Gordon Growth model, firms with higher dividend payout ratios will have higher price/book value ratios.

please explain why each choice wrong or correct