Can you help ID these pipes?

[Yippydadada]

Looking to purchase a home. Basement has rough-in plumbing but no labels. Can you help me identify pipes?Toilet is obvious, it seems two lower pipes (in photo) would be for venting. What really has me confused is why one pipe is different then the others, (on the left, capped and glued with space around pipe - 1~ inch space between concrete and pipe). Which would you guess is for shower, sink, venting? If there is ambiguity, how would you go about finding out? Pipe on top right and left is 2" pipe, bottom right is 2" pipe and I forgot to measure bottom left but it is smaller than the others. Thanks in advance!

 

[Sylvan]

Why not contact the local building department as plans were on file and then you can locate the plumber who filed the job and then you can ask them what they did