Assume a parent creates a thread immediately on start and does not join in. Assume the thread is scheduled by the kernel. The process' main function takes 1s of execution time, and the thread takes 2s of execution time.

a. On a single core processor, what is the total time(wall clock time) for execution? why?

b. On a multi-core processor, what is the total time(wall clock time) for execution? why?