Introduction:
In a computer system, the processor and memory are two crucial components that work closely together. The processor requires access to memory to fetch and store data. However, not all types of memory are easily interfaced with the processor. Among the options provided, dynamic memory is the most difficult to interface with the processor.

Explanation:
1. Static Memory:
Static memory refers to static random access memory (SRAM), which uses flip-flops to store data. SRAM retains data as long as power is supplied to it. It has a simple interface and is commonly used in cache memory, registers, and other high-speed memory applications. The processor can easily interface with static memory due to its straightforward addressing and data transfer mechanisms.

2. Dynamic Memory:
Dynamic memory, also known as dynamic random access memory (DRAM), is more challenging to interface with the processor. DRAM stores data using capacitors, and the information needs to be refreshed periodically to maintain its integrity. The refresh process consumes additional time and resources, making the interface more complex. Moreover, DRAM requires a separate controller to manage the refresh cycle, increasing the complexity further.

3. ROM:
Read-only memory (ROM) is a non-volatile memory that retains its contents even without power. It contains firmware or permanent data that cannot be modified. ROM typically has a straightforward interface, with the processor able to read data directly from the memory. Hence, ROM is not difficult to interface with the processor.

Conclusion:
Among the given options, dynamic memory (DRAM) is the most difficult to interface with the processor. Its refresh requirement and the need for a separate controller make the interface more complex compared to static memory (SRAM) and read-only memory (ROM). It is essential to consider the specific memory requirements and limitations when designing a computer system to ensure efficient communication between the processor and memory components.