When Crossing a True-Breeding Red Snapdragon Flower with a True-Breeding

When crossing a true-breeding red snapdragon flower with a true-breeding white flower of the same species, we secure all pink offspring. This would seem to support the pre-Mendel view that inheritance is a blending of parental traits. However, Mendel and conventional wisdom agree that "blending" of parental traits is not correct and that particles of inheritance are actually involved because

A) in the case of incomplete dominance, only radioactive isotope tracers can follow the actual hereditary particles.
B) under blending theory, over many generations only the average (or pink flowers) would remain; there would be no way to get back to pure red and white.
C) it is possible to cross the pink F-1 generation and secure a predictable proportion of pure red and white flowers again, which is not accounted for under the blending theory.
D) there is no way to directly prove incomplete dominance is not a case of blending, but we can be sure of genes because of the other cases of dominance, etc., where genes are the only logical explanation.
E) two of these are true.