Answer:
b. the uncompleted tasks were remembered better than the completed tasks
Step-by-step explanation:
The Zeigarnik effect was first discovered and studied by Bluma Zeigarnik, a Russian psychologist.
She published this phenomenon in her journal called 'Psychologische Forschung' in 1927 after establishing a number of experiments to apprehend how people tend to remember uncompleted task more easily than completed tasks.
Zeigarnik observed that people tend to remember uncompleted tasks because of task-specific tension which are relieved upon only after completion of the tasks.
Therefore, Zeigarnik effect pertains to the psychological phenomenon of recalling or remembering uncompleted or unfinished tasks better than the tasks which have been completed.