Question

What is defragmentation?

the process of removing unused space in a file or disk to reduce the amount of storage space necessary
the process of reorganizing data on the disk to store it more efficiently, with related data next to each other or in sequence
information about a computer file, distinct from the information it contains
the method used by operating systems to organize and store data

Answer 1

It would be option 2, "the process of reorganizing data on the disk to store it more efficiently, with related data next to each other or in sequence"

Step-by-step explanation:

Fragmented data is in fragments all over a traditional HDD (hard disk drive). Defragmenting this data will take those chunks from all over and place them sequentially. This can sometimes help speed up a hard drive as it won't have to search for each bit of data.