Round Your Answer to the Nearest Tenth, When Appropriate $\mathrm { pH } = - \log \left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right]$

Multiple Choice

Round your answer to the nearest tenth, when appropriate. Use the formula $\mathrm { pH } = - \log \left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right]$ , as
needed.
-Find the pH if $\left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right] = 7.9 \times 10 ^ { - 3 }$ .

A) 3.1
B) 3.9
C) 2.9
D) 2.1