The ionization constant of an acid-base indicator (a weak acid) is `1.0×10^(−6)` . The ionized form of the indicator is red whereas the unionized form is blue. The pH change required to alter the colour of the indicator from 80% blue to 80% red is:

Options

A. 2.00
B. 1.40
C. 1.20
D. 0.80