Balance the following equation: $SnO_2+H_2+Sn+H_2O$

Question

$\begin{array}{1 1} (a) 1SnO_2 +2H_2 \to 1Sn+2H_2O \\ (b) 1SnO_2 +3H_2 \to 1Sn+2H_2O \\ (c) 2SnO_2 +2H_2 \to 2Sn+2H_2O \\ (d)1SnO_2+2H_2 \to 1Sn+3H_2O \end{array} $