my question I will mark as you brain list​

A Polynomial is an equation in which variable x has positive integral power and the coefficient of x is not equal to zero.

According to this,

(i) and (ii) are the only Polynomials.

Reasons:

(iii) variable t has fractional power (i.e 1/2).

(iv) variable y has negative integral power.

(v)The question asks about polynomial in one variable. If y and t are taken as variables then this is not a polynomial in one variable.