Company z has an investment in an equity mutual fund. at the end of the year, the investment has declined in value as the stock market has deteriorated. how should z account for the loss in value:

A. write it down to fair value and record an unrealized loss on the income statement 

B. do nothing. leave the investment on the balance sheet at cost with no recording of the loss 

C. write the loss down to fair value and record the loss as part of stockholder's equity 

D. keep the investment on the balance sheet at cost but disclose the loss in the notes