Although there was once a time when child-adult sexual contact was more accepted, it is no longer ...

Although there was once a time when child-adult sexual contact was more accepted, it is no longer viewed as a normal expression of sexuality. What contributed to this?
 
  a. There was a population shift leading to a higher percentage of women than men; because of the surplus of unmarried mature women, men were discouraged from pursuing very young girls and encouraged to pursue more mature girls.
  b. Because of better nutrition and modern medicine, people began to live healthier and longer lives; thus, there was less pressure for men to marry very young women as a way to ensure reproductive success.
  c. In today's society, children are more outspoken and thus more likely to express their negative emotions about sexual contact with adults.
  d. Current child labor laws and compulsory education have changed societal views on the duration of childhood.