To arrange this polynomial in descending order, we must put the term with the highest degree exponent first and order the other terms until you reach the final term with the lowest degree exponent.
-4x+6x^3+2-2x^2+x^4
The highest degree is 4, and the lowest degree is constant (no variable), so the polynomial in descending order is shown below:
x^4 + 6x^3 - 2x^2 - 4x + 2
The question asks us to find the third term. To do this, we must count three terms in, starting from the left (remember that a term can be a coefficient and a variable; it is what is between the plus and minus signs).
This means that the third term is -2x^2, and your answer is C).
Hope this helps!