At the Beginning of the Year a Company Had a Debit

At the beginning of the year a company had a debit balance in the account Market Adjustment--Trading Securities.During the year the company did not buy or sell any trading securities,but at the end of the year the related market adjustment account had a credit balance.This change indicates that

A) a loss on the income statement was recognized.
B) a gain on the income statement was recognized.
C) the value of the investment account increased.
D) the value of the investment account decreased.