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

A) females invest more in sons because they have higher reproductive value.
B) when resources are limited, females invest more in sons because they are more likely to disperse.
C) lower quality females invest more in daughters because they are the cheaper sex to produce.
D) females adjust which sex they produce according to their body condition and ability to gather resources.