Answer:
4. Because of the coat color
Explanation:
If calico cats are female because of the color of their coats are determined by the X chromosome, then it comes to reason as the Y chromosome to be dominating seeing as the X chromosones are responsible for being the leading factor of the cat's sex. (I'm sorry if this is a sucky answer and I have no idea what the answers are to the rest but I hope this helps at least a little bit)
