The molecule is a cyclobutane (four-membered saturated ring).  

- Carbon-1 bears two substituents:  
  - a hydroxyl group.  
  - a straight n-propyl chain (three-carbon fully saturated chain).

- Carbon-3 bears a carboxylic acid group directly attached to the ring carbon.

- Carbons-2 and -4 carry no additional substituents.

There are no defined stereochemical requirements.