< b="" />Cache memory< />
Cache memory is a small, fast, and expensive type of memory that is located close to the CPU. It acts as a buffer between the CPU and the main memory (RAM), serving as a temporary storage for frequently accessed data and instructions. Cache memory is designed to provide fast access to data, reducing the time it takes for the CPU to retrieve information.

< b="" />Magnetic bubble memory< />
Magnetic bubble memory is a type of non-volatile memory that uses magnetic domains in a thin film to store data. It was popular in the 1970s and 1980s, but it has been largely replaced by other memory technologies. Magnetic bubble memory had a relatively slow access time compared to other types of memory, making it less suitable for applications that require fast data retrieval.

< b="" />Magnetic core memory< />
Magnetic core memory, also known as ferrite core memory, was one of the earliest types of computer memory. It used small magnetic cores to store data, and it was relatively slow compared to modern memory technologies. Magnetic core memory had a longer access time compared to cache memory.

< b="" />RAM< />
RAM, or random access memory, is a type of volatile memory that stores data and instructions that are actively used by the CPU. It is faster than magnetic core memory and magnetic bubble memory, but it still has a longer access time compared to cache memory.

< b="" />Conclusion< />
Among the given options, cache memory has the shortest access time. This is because cache memory is designed to be faster and more efficient in retrieving data compared to other types of memory. It is located closer to the CPU, allowing for quick access to frequently used data and instructions. On the other hand, magnetic bubble memory and magnetic core memory are older technologies that have slower access times. RAM is faster than the magnetic memories but still slower than cache memory. Therefore, cache memory is the memory with the shortest access time among the options provided.