When we have expressions that are connected by an equal sign "=", we have equations:
[tex]\begin{gathered} y=2x+1 \\ 13x^2=169 \end{gathered}[/tex]But when the equal sign is replaced by one of the symbols < or > (that is, lesser than or greater than), we have an inequality, because the value of the variable can't be determined exactly:
[tex]\begin{gathered} 2y>5 \\ x^2-4<0 \end{gathered}[/tex]So the correct option is D.
