36. The maximum allowance concentration of $PO_4^{3-}$ ion according to the Standard of eating and drinking water of WHO is 0.35mg/litre. To estimate the dirtiness of tap water in a city, 4.0 litre of that water sample is reacted with excess amount of $BaCl_2$ solution, forming $3.606 \times 10^{-3}$g of precipitate. Determine the concentration of $PO_4^{3-}$ in this sample of tap water, and consider whether this concentration is out of the allowance limit or not?
A. 0.285 mg/litre, within the allowance limit
B. 0.6 mg/litre, out of the allowance limit
C. 1.14 mg/litre, out of the allowance limit
D. 0.15 mg/litre, within the allowance limit