Mail not sending from the selected account.

In the preferences of Apple Mail, under the "Composing" section, when sending an email, you used to be able to choose a either a specific account or "send from the selected account" (not sure if the the wording is correct but it was something to that affect). Now all I'm able to select is 1., either a specific account, or 2., "Automatically select best account".

I noticed this because Apple Mail has been sending email from my wife's account and not mine. My wife and I use Apple Mail for all our email accounts on our Macs (not on our iPhone's) because we find it annoying to have to log in and out of separate users.

Anyway, you can see how this can become an issue when I send an email and the person on the receiving end sees it come from my wife and not myself.