Threads in User Space Can Be More Appropriate Than Kernel

Multiple Choice

Threads in user space can be more appropriate than kernel threads because ________.

A) user-level threads do not require the operating system to support threads.
B) application developers can tune the threading library's scheduling algorithm to meet the needs of specific applications.
C) user-level threads do not invoke the kernel for synchronization, which can reduce overhead.
D) all of the above