Yep, read your owners manual (OM) and follow their recommendation.
If it is just an "average" car that only requires API SN (or SM) oil, then any name brand Dino SN oil will work fine. However, if you want a better oil, then I agree with lubricatosaurus, and suggest you get a Dexos-1 (and SN) oil. Easy to find and a higher performance level is required to meet this standard.
As you go up in manufacturer standards, you tend to also go up in add pack and in the base oil used. That's why I recommend studying and choosing a few manufacturers standards that you like as a simple way forward.
For MB 229.5 oil, I have only seen this oil as a full synthetic, with a heavy add pack.
For ACEA A3/B4 or Dexos, I have only seen or heard of these oils as either full synthetics or semi-synthetics.
For API SN, this is easy to find as a dino oil. But all of the above should still be SN rated, so of course it also exists as a semi or full synthetic.
SN (with the correct viscosity required by you manufacturer) is your base requirement, then you can add other manufacturer's standards on top of this SN base (e.g. Dexos) to improve the quality of the oil used. Stick to name brand oils, plus a good filter, and you can't go wrong.