Degree of the polynomial of \[4{x^4} + 0{x^3} + 0{x^5} + 5x + 7\] is

The height power of the variable in a polynomial is called the degree of the polynomial. In this polynomial, the term with highest power of x is \[4{x^4}\]Highest power of x is 4, so the degree of the given polynomial is 4.
Hence, (a) is the correct answer.