A fifth-degree polynomial with leading coefficient 4

Easy

leading coefiencet means highest power coefient

degree is the power of the highest exponent

5th degree and leading coefienct is 4

means highest exponet is 5 and the coefienct is 4

means any thing with 4x^5 such that there is no x^n where n>5

4x5 + 3x + 1 is the answer (2nd one)