Answer:
Fully associative
Explanation:
Fully associative cache is a type of cache in which after retrieving the data from memory, it subsequently allows data to be deposited in the available but unused cache block. This is to ensure that the storage of cache is done without forcing each memory address into one specific block.
Given the following
address = 32 bits,
tag = 28 bits, as a block is 4 words that are, 4x4 bytes,
offset = 4 bits, which equates to index = 0 bits.
Hence, it can be concluded that the type of cache is FULLY ASSOCIATIVE.