Harlow Shapley's Original Estimate of the Distance from the Sun

Harlow Shapley's original estimate of the distance from the Sun to the galactic center was incorrect because it did not take interstellar extinction into account.This original estimate was

A) too large because light scattering and absorption by dust made nearer stars look dim-as though they were more distant.
B) too large because scattering by dust made stars look redder-as though they were highly Doppler shifted and thus more distant.
C) too small because gas and dust tend to reflect light back into the path of the beam,thus making stars look brighter and nearer.
D) too large because scattering by dust made stars look redder-as though they were red giants of larger luminosity and thus farther away.