How was Mendel’s work ultimately reconciled with Darwin’s theory of Natural Selection during the evolutionary synthesis in the 19-?0s and 1940s ?

(a) Mendel's theory was replaced by the mutation theory.

(b) It was recognised that much of the variation we observe in nature is due to recombination. rather than mutation.

(c) Scientists recognised that once one thinks about species as populations, rather than individuals there is no incompatibility between them.

(d) Both (b) and (c).