Identify the valid cache organization techniques: (i) Direct (ii) Associative…

Cache mapping technique is the rule that decides which cache line (or lines) a given block of main memory is allowed to occupy. Computer architecture recognizes exactly three such techniques: direct mapping (each block maps to exactly one specific line, found from the block address), (fully) associative mapping (a block may be placed in any line, so every line's tag must be compared to locate it), and set-associative mapping (the cache is divided into sets; a block maps to one specific set but can occupy any line within that set, combining the previous two ideas).

The stem lists exactly these three schemes as (i) Direct, (ii) Associative, and (iii) Set-associative. Each one is a distinct, standard entry in this classification, so none of the three can be dropped from a complete answer -- the correct selection has to name all three together.

• (i) and (ii) only -- leaves out set-associative mapping, the scheme that groups the cache into sets and allows any line within the assigned set.

• (ii) and (iii) only -- leaves out direct mapping, the scheme that fixes a block to exactly one specific line.

• (i) and (iii) only -- leaves out (fully) associative mapping, the scheme that allows a block into any line and compares every tag to find it.

Since each of the three named schemes is a valid, independent cache organization technique, the combination that lists (i), (ii) and (iii) together is the only complete and correct selection.