Q. It is widely assumed that pregnancy and motherhood turn women into sieve-brained shadows of their former selves: the condition called "mummy brain" or "baby brain" is a familiar staple of popular culture. But when Tombeau Cost started digging through the scientific literature, she found little evidence to support it. Indeed, she found evidence to the contrary- at least in rats, ___________________________.
Which of the following best completes the passage above?
A. which become mentally sharper after giving birth.
B. which show few signs of mental slowdown after giving birth.
C. which show no signs of mental slackness after giving birth.
D. which enter a state of delirium after giving birth.