Multiples answers are allowed

Assume you want to implement a web$-$server for YouTube by using multithreading, where each thread serves one incoming request by loading a video file from the disk. Assume the OS

only provides the normal blocking read system call for disk reads, do you think ULTs or KLTs should be used?

Select the statements that are properly matched to achieve this goal.

In this case, it is recommended to use ULTs for its efficiency as one thread can block all other threads within the same process.

It is better to use KLT$,$ because one thread won't block others.

It is recommended to use KLT because each thread will make blocking I$/$O calls.

Using ULT, one thread will block all other threads which is suitable for $\frac{1}{O}$ operations.

In this case, using KLTs which is more expensive, is not a matter as everytime such communication needs anyway to go through the kernel.

In this particular case, it is beneficial to implement ULTs since these threads need to communicate frequently with each other.