A reference solution of a food-dye exhibits an absorbance of 0.450 when its concentration is 2.0×10−4M in a 1.00 cm cuvette. An unknown solution of the same dye measured under identical conditions shows an absorbance of 0.675. What is the concentration of the unknown solution?
a) 2.67×10−4M
b) 3.0×10−4M
c) 6.0×10−4M
d) 1.33×10−4M