A multiple choice test consists of 4 questions, and each question has 5 answer choices. In how many F ways can the test be completed if every question is unanswered?  Choose the most appropriate option.
A) 24	B) 120	C) 625	D) 720	E) 1024

Rationale: "5 choices for each of the 4 questions , thus total f of 5 * 5 * 5 * 5 = 5 ^ 4 = 625 ways to answer all of them . answer : c ."
Answer: C