What is the fifth term in the binomial expansion of (x + 5)8?

In the expansion of (x + 5)^8, the fifth term uses r = 4 in the binomial formula: C(8,4)x^(8−4)5^4. Since C(8,4) = 70 and 5^4 = 625, the term is 70 × 625x^4 = 43,750x^4. The fifth term is 43,750x^4, choice B.

AI-written and checked against the verified answer.