Drum master cylinder push rod length

Silly me threw out the old master cylinder and push rod. The new one came with 2 different push rods. Which one do I use?

Manual or power brakes?

I once had that issue, the long one was for manual brakes, where the short one was for the vacuum power booster. but these 2 rods were very different in length so it was obvious. if you have to guess Take off the locking clip off the rod and test fit. then place the clip on the rod and send her home. once the clip locks in you cant get it out.