Imagine That the Following Are Found in Various Research References

Imagine that the following are found in various research references. Which would likely be considered a "dated" research reference, regardless of year of publication?

A) Rates of autism are rising at never-before-seen rates.
B) Cones are tightly packed in the center of the retina, allowing for high visual acuity.
C) Freud believed that much of our behavior is the result of unconscious urges.
D) Implantation of the blastocyst occurs within 6 to 10 days after conception.