Please give the reason?

10. When conducting comparative analysis by reviewing consecutive balance sheets: | KI + A. all items on the balance sheet in Year t must be divided by their corresponding value in Year t-1 and subtract 1 to calculate the percentage change. B. all items on the balance sheet in Ye J-1 must be subtracted from their corresponding value in Year t to calculate the dollar change. C. all items on the balance sheet in Year t must be divided by net income in Year t-1 to calculate the percentage change. D. Both A and B are correct