In the titration of a weak acid HA with 0.100 M NaOH, the stoichiometric point is known to occur at a pH value of approximately 8. Which of the following indicators would be best to use to mark the endpoint of this titration?
A) an indicator with Ka = 10^(-11)
B) an indicator with Ka = 10^(-14)
C) an indicator with Ka = 10^(-9)
D) an indicator with Ka = 10^(-8)
E) an indicator with Ka = 10^(-12)
(a) D
(b) E
(c) C
(d) A
(e) B