Paragraph 4 strongly suggests that the theory of continental drift was not widely accepted before the 1960s in part because A. the distributions of fossils such as Glossopteris were not yet generally known B. other explanations for the geometric fit of South America and Africa were available C. there was no satisfactory explanation for the movement of continents D. few scientists accepted the claims made by Wegener and du Toit about the similarities in the ages of groups of rocks