Which function is nonlinear

Answer:
Only 3rd one is exponential and non linear.
Step-by-step explanation:
Linear functions are in the form of [tex]y=mx+c[/tex] and have a constant slope.
Nonlinear functions have a slope that varies between points.
Also, the linear functions are polynomials with highest exponent equal to 1 and all others are non linear.
Here, only option 3rd is not linear or non linear.
Other options are all in the form of [tex]y=mx+c[/tex] means linear.
Only 3rd one is exponential and non linear.