Interrupt Latency:
Interrupt latency refers to the time taken by a system to respond to an interrupt request. When an interrupt occurs, it is crucial for the system to respond promptly in order to handle the interrupt and resume the interrupted task. The delay between the occurrence of an interrupt and the beginning of its processing is known as interrupt latency.

Understanding the Options:
Let's go through the given options to understand them better and identify the correct answer:

a) Interrupt Delay: This option is incorrect as it does not accurately describe the time taken to respond to an interrupt. Delay implies a pause or wait, which is not the case for interrupt processing.

b) Interrupt Time: This option is not the correct answer as it is a vague term and does not specifically refer to the time taken to respond to an interrupt.

c) Interrupt Latency: This is the correct answer. Interrupt latency precisely represents the time taken to respond to an interrupt. It encompasses the time required for the system to recognize the interrupt, save the current state of the interrupted task, and begin processing the interrupt.

d) Interrupt Function: This option is not the correct answer as it does not represent the time taken to respond to an interrupt. Interrupt function typically refers to the software routine or code that handles the interrupt once it has been acknowledged.

Conclusion:
The correct answer to the given question is option 'C', interrupt latency. Interrupt latency represents the time taken by a system to respond to an interrupt request. It is crucial for a system to minimize interrupt latency to ensure efficient interrupt handling and timely resumption of interrupted tasks.