When 30% of Another Company's Common Shares Are Purchased for a Price

When 30% of another company's common shares are purchased for a price in excess of 30% of the market value of its net assets, why is the excess of market value of assets over its book value amortized by the investor over its remaining useful life?

A) That part of the investment is overstated in value at acquisition date.
B) The investee's income is understated with respect to the price paid by the investor for the shares.
C) The investee's income is overstated with respect to the price paid by the investor for the shares.
D) To correct errors in the investee's accounting.