Electricity transmission is a bit like water pressure and distribution. You're not going to get the same electrons (or water molecules) that you subscribed to from various producers in the distribution network put in, the flow causality and the physical embodiments of production are different though related things.

Since your supply is alternating current, the electrons aren't net moving at all.

The question isn't even well-formed. It's like playing tug-of-war and asking exactly which player on the other team you're pulling against.