The correct answer is C. 15.
A SPARC processor supports 15 external interrupts. These interrupts are used to signal the processor that an event has occurred that requires its attention. The interrupts are numbered from 0 to 14, and each interrupt has a corresponding interrupt vector. The interrupt vector is a memory location that contains the address of the interrupt service routine. When an interrupt occurs, the processor saves the current state of the CPU and then branches to the interrupt service routine. The interrupt service routine then handles the event that caused the interrupt and then returns to the interrupted instruction.
The following are the 15 external interrupts supported by a SPARC processor:
- Interrupt 0: Reset
- Interrupt 1: NMI (Non-Maskable Interrupt)
- Interrupt 2: IPI (Interrupt Priority Interrupt)
- Interrupt 3: Timer Interrupt
- Interrupt 4: Keyboard Interrupt
- Interrupt 5: Serial Interrupt
- Interrupt 6: Parallel Interrupt
- Interrupt 7: DMA Interrupt
- Interrupt 8: System Call Interrupt
- Interrupt 9: User Interrupt
- Interrupt 10: Hardware Interrupt
- Interrupt 11: Software Interrupt
- Interrupt 12: Watchdog Timer Interrupt
- Interrupt 13: Performance Counter Interrupt
- Interrupt 14: Machine Check Interrupt