I'll give the contrarian opinion.
Neither guy is particularly suited for second, but Player B's arm would be an absolute disaster at third - Player A is no Brooks Robinson either, but at least he'll be able to stop the ball from leaving the infield (unless he tosses it past the 1B).
It seems to me that HBD has always been easier on 2Bs than it should be - range ratings seem to have less effect on 2Bs even though in RL they usually make more plays per game than SSs. Furthermore, a missed play by a 2B generally means a single, whereas a miss by a 3B could be a double. So ... given your situation I'd put Player A at third.
Alternatively, you could just sign Salazar to play 2B and steal bases. Or, since I have plenty of depth at MIF you could try to swing a deal for a 2B or an SS that could slide over to 3B. Lemme know if you're interested.
FINAL NOTE: Given the most recent update regarding plus plays, the above reasoning about 2B may no longer be valid - if they are going to be rewarding good fielding, they may start penalizing bad fielding as well.