Comparing an unknown solution that has been diluted 8.333-fold to a standard curve indicates that the diluted unknown solution has a concentration of 0.0340 M. What was the concentration of the unknown solution before it was diluted?
A.0.00408 M
B.245 M
C.0.283 M
D. 0.211 M
Express your answer to two significant figures and include the appropriate units.