Write the correct alternative answer for the following question.
Which of the following is a polynomial ?
`x^(sqrt2) - 3x`
`x^(-2) + 7`
`sqrt2 x^2 + 1/2`
In an algebraic expression, if the powers of the variables are whole numbers then the algebraic expression is a polynomial.
In the expression `sqrt2 x^2 + 1/2`, the power of the variable x is 2, which is a whole number. So, the expression `sqrt2 x^2 + 1/2` is a polynomial.