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

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