Which of the following expressions are polynomials in one variable and which are not? State reason for your answer. If the given expression is a polynomial,state whether it is a polynomial in one variable or not: $x^{2}-8x+15$

(A) The given expression is $x^{2}-8x+15$.
In this expression,the variable is $x$.
The exponents of $x$ in the terms $x^{2}$,$-8x^{1}$,and $15x^{0}$ are $2, 1$,and $0$,respectively.
Since all these exponents are non-negative integers,the expression is a polynomial.
Furthermore,since there is only one variable $x$ present in the expression,it is a polynomial in one variable.