Final answer:
The two interrupt request lines are a) Nonmaskable interrupt and c) Maskable interrupt. Maskable interrupts can be disabled by the CPU, while nonmaskable interrupts cannot be ignored and must be processed immediately.
Step-by-step explanation:
In general, the two interrupt request lines are: c) Maskable interrupt and a) Nonmaskable interrupt. A maskable interrupt is an interrupt that can be turned off or ignored by the processor typically done by setting a bit in an interrupt mask register. This allows the CPU to avoid interruptions during critical processing periods.
On the other hand, a nonmaskable interrupt is a higher priority interrupt that cannot be ignored by the processor and must be dealt with immediately. It is typically used in events of emergency like power failure or a system crash that require immediate attention.