In which of the following compounds does hydrogen carry a negative oxidation state (using Pauling values H 2.20, Li 0.98, B 2.04, Si 1.90, C 2.55)?

Hydrogen is assigned $-1$ whenever the other atom is less electronegative than H (2.20). Li (0.98), B (2.04) and Si (1.90) are all lower, so H is $-1$ in $\mathrm{LiH}$, $\mathrm{B}{}_2\mathrm{H}{}_6$ and $\mathrm{SiH}{}_4$. C (2.55) is higher, so in $\mathrm{CH}{}_4$ hydrogen is $+1$.