A straight rail subway, which is 8 meter long, has P and Q as its two openings. A man stands inside the subway 3 meter away from the opening P, when he notices a train about to enter the subway from the opening P. If the man, immediately after noticing the train, runs with his maximum speed towards the opening P, the train kills him right at the opening P; and if he immediately runs with his same maximum speed towards the opening Q, the train kills him right at the opening Q. At what distance, in meter, from the opening P, was the head of the train, when the man first noticed the train?
(A) 20
(B) 15
(C) 12
(D) 10
(E) 8