What did you learn from the links Sra posted yesterday when you asked this identical question??
i am not sure L1 OR L2,it could be L1
this is litle bit hard for me because is second language
a. is correct.
L1,L2... stand for Level 1 cache, Level 2 cache, etc.
A cache memory is a high speed memory that stores information that is used over and over again. This way, the computer's central processing unit (CPU) does not have to wait for the information to be loaded from slower memory, or even the disk.
Level 1 cache is built in, and becomes part of the CPU chip, so it is almost always present in a personal computer. It is usually very fast static memory that does not require frequent refreshing (hence less time lost).
Level 2 cache can be present as a separate memory chip, or at times also built into the processor. This way, most personal computers almost always contain L2 memory.
Level 3 is slower, and usually has a larger capacity.
Level 4 memory is even larger and slower. However, a the benefits of a huge cache is doubtful. Therefore the presence of L4 memory in personal computers is not guaranteed.