19. When considering the propagation of uncertainty with a calibration curve from linearregression, which of the following approaches or conditions does not help narrow downthe uncertainty (Sx) of the unknown concentration [X]?
(A) to achieve a greater slope for the calibration curve
(B) to have more data points for the calibration line
(C) to increase the number of replicate measurements of the unknown
(D) the signal or response of the unknown to be at the far ends of the calibration line
(E) a correlation coefficient closer to unity