Solve the Problem $= - \log \left[ \mathrm { H } ^ { + } \right]$

Solve the problem.
-In the formula pH $= - \log \left[ \mathrm { H } ^ { + } \right]$ , the variable $\mathrm { pH }$ represents the level of acidity or alkalinity of a liquid on the $\mathrm { pH }$ scale, and $\mathrm { H } ^ { + }$ is the concentration of hydronium ions in the solution. Determine the value of $\mathrm { H } ^ { + }$ (in $\mathrm { mol } / \mathrm { L }$ ) for a liquid, given its $\mathrm { pH }$ value. Round to 2 significant digits. $\mathrm { pH } = 10.1$

A) $7.9 \cdot 10 ^ { - 11 } \mathrm {~mol} / \mathrm { L }$
B) $- 7.9 \cdot 10 ^ { - 10 } \mathrm {~mol} / \mathrm { L }$
C) $- 7.9 \cdot 10 ^ { - 11 } \mathrm {~mol} / \mathrm { L }$
D) $7.9 \cdot 10 ^ { - 10 } \mathrm {~mol} / \mathrm { L }$