The correct answer is: D. A co-processor
A co-processor is a specialized processor that assists the main processor in performing certain tasks. This can reduce the processing time of those tasks, as the co-processor can handle them more efficiently than the main processor.
A buffer is a temporary storage area that can be used to hold data while it is being processed. This can help to improve performance by reducing the amount of time that the main processor has to wait for data to be available.
An EPROM is a type of memory that can be erased and reprogrammed. This can be useful for storing data that needs to be updated frequently, such as system configuration information. However, EPROMs are not typically used to improve processing time.
A converter is a device that converts data from one format to another. This can be useful for transferring data between different systems or devices. However, converters do not typically improve processing time.
Therefore, the only option that can reduce processing time is a co-processor.