Refer to the figure, which shows the provisioning efficiency of female red mason bees. These findings indicate that

A) females have a higher provisioning efficiency than males.
B) in the beginning of the season the sex ratio of offspring is skewed male, but by the end of the season the sex ratio is biased towards females.
C) at lower provisioning efficiency, the sex ratio of offspring is skewed male, but at higher provisioning efficiency, the sex ratio is biased towards females.
D) females that are able to provision more efficiently are more likely to produce sons than daughters.