Answer is C.
Both Vectored interrupts and multiple interrupting devices are both possible.
You know about parallel & serial connection(Daisy Chain).
Multiple devices are connected serially.
This is how it looks like.
So how it handles multiple interrupts ?
By the way what does it mean by handling multiple interrupts?
It means handling the interrupt from multiple I/O devices, & when two or more devices cause interrupt simultaneously, we want to give priority to High priority I/O.
The way it is implemented is....
Even if one I/O device caused interrupt, we can know it... but who raised it ?
Interrupt ACK is connected to I/O1 (I/O with Highest priority)
If the interrupt was caused by I/O1 then, it will not forward the signal to I/O2. So we can know it was caused by I/O1.
If it was caused by I/O3, then I/O1 will forward it, I/O2 wil forward it .. So it is caused by I/O3.
So we are checking from highest priority I/O to lowest priority.
If two or more device cause interrupt, then priority will be given to higher priority since ACK moves from highest priority, so it will not forward ACK, & we can know we have to serve it first.