it depends. its hard because its not clear what you need this pg for - what abilities are most important - as well as what system you play, and what the other ratings are (reb, def, lp, sta, ft%).
based on the limited information at hand, if you have a strong offensive starting lineup (at the other 4 positions), especially with a strong passer at sg and possibly even sf, it would make player A the easy choice. on the other hand, if your offense is lacking, and you have no other 3 point shooting to speak of, it makes player B the easy choice. it really depends on the circumstances, if you want to elaborate, i'd be happy to take another crack at it! you don't have to enumerate all the other players, but if you can summarize, with some details on the SG in particular, thats probably enough. for example, on the big 4 abilities - offense, defense, guard skills, and rebounding (although rebounding matters less here, obviously) - how does the rest of your starting lineup stack up? what are the PGs's other ratings, and what sets do you run? offensively, how does your defensive line stack up? this last bit matters because that player B would be a great backup if you have enough offense on the starting lineup but crap offense on the backup line.