Answer
Choice D
Work Step by Step
Since $|x|=c$ implies $x=c \text{ or } x=-c,$ then the the given inequality, $
|2x+1|=3
,$ is equivalent to
\begin{array}{l}\require{cancel}
2x+1=3 \text{ or } 2x+1=-3
.\end{array}
Hence, $\text{
Choice D
.}$