It isn't. Both aren't even theories, but products of simpleton invention without basis and are completely undoubtedly incorrect. I favor none. I delete(d) them both, because AFAIK there are none sources at all on this issue. 
The House of Saint Vladimir is of descent from a Travunian local noble house, with doubtable links to the House of Trpimirovic and most surely no link to the House of Viseslavic. 
However, I must object putting it as a separate line - Tvrtko asserted rule and his line (Tvrtkovic) is historically considered the main line of the Kotromanics. As for the Trpimirovic branches, I suggest following standard historical interpretation of the Svetoslavic being a cadet branch, whereas the other being the simple continuation of the standard Trpimirovic line (Kresimirovic)?