Regarding the interrupt service subroutine, consider the following tasks:
A. Turn the interrupt facility on
B. Service the device whose flag is set
C. Save the contents of processor registers
D. Check which flag is set
E. Restore the contents of processor registers
Choose the correct answer from the options given below:

1. AA, D, C, B, E
2. BD, A, B, C, E
3. CC, D, B, E, A
4. DB, D, A, C, E

Pick an option to check yourself, or open the answer below.