The correct option is 4.
Step-by-step explanation:
Domain is the set of all possible inputs for which the given function is defined.
The given function is
![y=x^2-6x+1](/tpl/images/0279/0374/17e9e.png)
It is a second degree polynomial. These type of polynomial are defined for all real values of x. So, the domain of the given function is all real numbers.
![Domian=\{x:x\in R\}](/tpl/images/0279/0374/ea6cf.png)
![Domian=R](/tpl/images/0279/0374/62f4f.png)
Therefore the correct option is 4.