Remark
First of all we know that the contamination is not from heavy metals. So the first column is not included in our calculations. You only need to worry about the last 4 columns.
Givens.
Column B = 0.15%
Column C = 0.28%
Column D = 0.33
Column E = 0.31 Total these
Total = 1.07%
Now that's not the answer. If there is Bacterial Contamination the % is
(0.31/1.07) * 100 = 28.972% which when rounded is 29%
B <<<<< Answer