No idea about the 2015 edition.
You elected to use the criteria for connections that are nontubular and statically loaded. So, only the first paragraph, A, applies. If you have a CJP groove weld, no piping porosity is permitted. For all other welds, only porosity larger than 1/32 inch in diameter has to be considered. Now, be careful, the code is [url=]only concerned with piping porosity[/url]. There is a definition in Annex K to clarify what piping porosity is.
Each paragraph, A, B, and C, are independent of the other.
Best regards - Al