Given:
The function is:

To find:
The domain of the given function.
Solution:
Domain is the set of input values.
We have,

It is a quadratic polynomial.
We know that a quadratic polynomial is defined for all real values of x. So, the given function is defined for all real values of x and the domain of the given function is:
Domain = Set of all real number
Domain = (-∞,∞)
Therefore, the correct option is B.