Why Was Wundt's Landmark Book Principles of Physiological Psychology (1874)important

Multiple Choice

Why was Wundt's landmark book Principles of Physiological Psychology (1874) important?

A) It was the first genuine "textbook" describing under one cover several recent developments in the area of experimental psychology.
B) It focused attention on the originality and variety of Wundt's own experiments.
C) It introduced the work of early female psychologists.
D) both a and b above