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

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