Help with understanding move

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inherentmediocrity
Hi everyone!
Can someone please explain why this is the best move? Why not Room to B1
[Site "Chess.com iPhone"]
[Date "12/28/2019 01:14PM"]
[White "inherentmediocrity (0)"]
[Black "Computer (Level 3) (0)"]

1.e4 Nf6 2.Nc3 d5 3.exd5 Nxd5 4.Nxd5 Qxd5 5.Nf3 Qd7 6.d4 Qf5 7.Bd3 Qd5 8.Be3 Qc6 9.O-O h6 10.Ne5 Qb6 11.b3