D quadratic
Explanation
[tex]f(x)=(x+1)^2[/tex]
you can easily identify a function with this :
if the exponent of the variable (x) is 1 , then it is a linear function:example
[tex]\begin{gathered} y=x,\text{ linear function} \\ y=3x+8 \end{gathered}[/tex]if the exponent of the variable (x) is 2 , then it is a quadratic function
[tex]\begin{gathered} y=x^2 \\ y=(x+1)^2 \end{gathered}[/tex]the absolute value has this symbol
[tex]y=\left|x\right|[/tex]a constant function is a number, with no variable, example
[tex]\begin{gathered} y=4 \\ Y=-7 \end{gathered}[/tex]so, the answer is D quadratic