Which of the following functions is quadratic?
O A. f(x) = 7x(x+3)
OB fx) = 5/x-1
O c. f(x) = 2^2
O D. f(x)=3(4 – x)
![Which of the following functions is quadratic O A fx 7xx3 OB fx 5x1 O c fx 22 O D fx34 x class=](https://us-static.z-dn.net/files/d6f/41f6f66124e28f4461dbe36a3e7ff526.png)