Four candidates presented themselves to take the exam of a competition. Before starting the exam, the cell phones of the four candidates were collected by the proctor, who stored them, each one, inside a black envelope. At the end of the exam, the proctor returned the four envelopes with the cell phones to the four candidates, in a random manner, since he had not identified the envelopes. The probability that all candidates received back the envelopes with their respective cell phones is (A) $\dfrac{1}{2}$ (B) $\dfrac{1}{10}$ (C) $\dfrac{1}{16}$ (D) $\dfrac{1}{24}$ (E) $\dfrac{1}{256}$
Four candidates presented themselves to take the exam of a competition. Before starting the exam, the cell phones of the four candidates were collected by the proctor, who stored them, each one, inside a black envelope. At the end of the exam, the proctor returned the four envelopes with the cell phones to the four candidates, in a random manner, since he had not identified the envelopes.
The probability that all candidates received back the envelopes with their respective cell phones is\\
(A) $\dfrac{1}{2}$\\
(B) $\dfrac{1}{10}$\\
(C) $\dfrac{1}{16}$\\
(D) $\dfrac{1}{24}$\\
(E) $\dfrac{1}{256}$