$56$:$07$

In order to join more than two datasets with only visual recipes, which of the following solutions is correct and why?

None of these.

It is not possible to join more than two datasets at a time with the Join recipe. Perform multiple Join recipes instead.

Provided it is a left join, a single Join processor of the Prepare recipe is capable of joining more than two datasets at a time.

Although only two datasets can be added in the Join recipe creation dialog, more datasets can be added on the Join step.