What length of unthreaded one inch gas pipe should be exposed when stubbed out from a finished wall

Dje530:

You need to tell us more than that... ;)

You said UNthreaded..? Why..? Not attaching anything?

Stubbed out from finish wall..? Why?

Let us know more. Thanks.. Mark

It's a question on a plumbing quiz and I don't know the answer. NO othe rinfo

It's a question on a plumbing quiz and I don't know the answer. NO othe rinfo
Got to be a trick question! I'm going after this question the practical way. Since the pipe coming out of the wall's unthreaded black iron pipe and compression fittings can not be used a thread must be put on that bald piece of pipe.
Soooo, a 1 inch ratchet dye,(See image, no room to swing a block dye pipe threader) will take up close to three inches I would say that piece of pipe should be at least three and a half inches out from the wall. And I would add a footnote saying that, as a plumber, I would NEVER terminate a black iron gas supply without a thread.
While this probably isn't the answer they want this is the one that will get your gas appliance connected. Good luck on your test. Tom