Answer
$n, a_n, a_0$
Work Step by Step
Look at the definitions of the degree of a polynomial, leading coefficient of a polynomial and the constant term of a polynomial on page 28.
Degree of a polynomial = n (It is the maximum of the degrees of its monomials / terms with non-zero coefficients.)
Leading coefficient of a polynomial = $a_n$ (The coefficient of the term with the highest power)
Constant term of a polynomial = $a_0$ ( term of degree 0)