Subject - Threads in Operating System

NPTEL OS Quiz Question

Q. Degree of concurrency in threads can be arranged in the manner

 A : One-to-one > many-to-one > many-to-many
 B : One-to-one > many-to-many > many-to-one
 C : Many-to-many > many-to-one > one-to-one
 D : None of the above

Answer given is A. Someone please confirm.