The firm's book value of assets increases by $100M, while the firm's total liabilities (excluding shareholder equity) decreases by $50M. Retained earnings decline by $20M. What happens to the book value of common and preferred stock?

A) This is impossible, the firm's balance sheet wouldn't be balanced

B) The book value of common and preferred stock increases by $150M

C) The book value of common and preferred stock increases by $170M.

D) The book value of common and preferred stock increases by $70M