A result of the common-ion effect is ________.
a. that common ions, such as Na+ (aq), don't affect equilibrium constants.
b. that some ions, such as Na+ (aq), frequently appear in solutions but do not participate in solubility equilibria
c. that the selective precipitation of a metal ion, such as Ag+, is promoted by the addition of an appropriate counterion (X-) that produces a compound (AgX) with a very low solubility
d. that common ions precipitate all counter-ions
e. that ions such as K+ and Na+ are common ions, so that their values in equilibrium constant expressions are always 1.00