Answer:
The word in blank will be Readability
Step-by-step explanation:
Because readability has major role in maintenance of programs because when a program is written and after some year a company wants to upgrade the software or wants to remove bugs and issues so company maybe re analyze the program and if the programmer of that program has left the job than readability of program will help new programmers working on that software to understand that what mistake is done and where is done. Readability also helps programmer of that code to understand his own logic.