Mendel Was Able to Draw His Ideas of Segregation and Independent

Mendel was able to draw his ideas of segregation and independent assortment because of the influence of which of the following?

A) His reading and discussion of Darwin's Origin of Species
B) The understanding of particulate inheritance he learned from renowned scientists of his time
C) His discussions of heredity with his colleagues at major universities
D) His reading of the scientific literature current in the field
E) His experiments with the breeding of plants such as peas