Absolute value: C
Quadratic: D
Constant: A
Square root: E
Linear: B
There are the equations for the graphs on the bottom:
y=2 is constant because the y value never changes
y=x is linear because the y value changes at a constant rate
y= |x| is absolute value because |x| is the absolute value of x
y=x^2 is quadratic because quadratic functions have a degree of 2
y=sqrt(x) is a square root because y= square root of x