In a calibration plot of absorbance (A) versus concentration (c) for a colored species measured with a fixed 1.00 cm cuvette, the slope of the best-fit line most directly represents which of the following quantities?
a) εb (molar absorptivity multiplied by path length)
b) the molar absorptivity of the species, ε
c) 2.303ε (molar absorptivity converted from natural–log form)
d) 2.303ε (molar absorptivity converted from base-10 to natural-log form)