The one and the negative one
Yes, because the sample is random. If she had chosen the participants in any way other than randomly, it would not be representative of her entire school.
Answer:

Step-by-step explanation:
Quadratic function-
It is a function that can be represented by an equation of the form
, where
In a quadratic function, the greatest power of the variable is 2.
As in the first option the highest power is 3, so it is not a quadratic function.
Even though the power of x is 2 in the third option, but as it is in the denominator, so the overall power of x becomes -2. Hence it is not a quadratic function.
As the coefficient of
is 0 in case of fourth option, so it is not a quadratic function.
Equation in option 2 satisfies all the conditions of quadratic function, hence it is the quadratic function.