To maximize the use of available space, $\_\_\_\_\_\_\_\_$ combines adjacent holes in memory, while $\_\_\_\_\_\_\_\_$ relocates all occupied areas of memory to one end of main memory, leaving a single large free memory hole instead of numerous small holes.

internal fragmentation, external fragmentation

compaction, coalescing

coalescing, compaction

variable$-$partition multiprogramming, fixed$-$partition multiprogramming