How do I restore 'Reopen all windows from last session' option in Safari on Mac?

I have gotten used over time to keep my tabs open. I wondered how it happened but all tabs lately are gone quite often. Was it a burglar? A hacker? My iMac?

But what ever it was it turned out to be easy to restore the tabs with the option to "reopen all windows from last session" in history . . .

Now it is how ever gone.

I found this question on this platform from earlier, yet the reply was the total opposite of an answer, it explained how to "close" all windows.

So I am asking again and I hope someone will be able to help.