Answer:
A. Eventually he gave up, saying, "The problem is too complicated, scientifically insoluble."
B. But Akerblad's success in identifying so many demotic characters now led him to make a serious mistake.
C. It was like the inspired hunches that have led so many of the great advances in science and technology over the ages.
D. Because of this mistaken belief, Young put roadblocks in his own path.