The correct option is A 31500
From the histogram shown in the question, notice that there are 3 bricks corresponding to the year 2008. Since each brick represents 10,500 CDs sold, in the year 2008, the no, of CDs sold would be 3 times that of 10,500 (because frequency is 3, i.e. the number of bricks in the year 2008).
Therefore, the total no. of CDs sold in 2008 = 3 x 10,500 = 31500.