Tail-Feather Length in Birds Is Sometimes a Sexually Dimorphic Trait

Multiple Choice

Tail-feather length in birds is sometimes a sexually dimorphic trait. That is, the trait differs substantially for males and for females. Researchers studied the relationship between tail-feather length (measuring the R1 central tail feather) and weight in a sample of 20 male and 21 female long-tailed finches raised in an aviary.
What is the value of the y intercept for the male regression line (blue squares) ?

A) Approximately 70 mm
B) Less than 50 mm
C) 0 mm
D) Cannot be guessed from the graph