Which of the following features will characterize an OS as multi programmed OS?(a) More than one program may be loaded into main memory at the same time.(b) If a program waits for certain event another program is immediately scheduled.(c) If the execution of a program terminates, another program is immediately scheduled.

• A. (a) only
• B. (a) and (b) only
• C. (a) and (c) only
• D. (a), (b) and (c) only