Which of the Following Statements About Kernel-Level Threads Is False

Which of the following statements about kernel-level threads is false?

A) The kernel can manage each of a process's threads individually.
B) A process that uses kernel-level threads often can adjust the level of service each thread receives from the operating system.
C) Software that employs kernel-level threads often is more portable than software that employs user-level threads.
D) Kernel-level threads require the operating system to manage all threads in the system.