
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
At the start of the semester, 40% of students in a university course preferred online classes while 60% preferred traditional classes. By the end of the semester, 80% of the students preferred online classes and 20% preferred traditional classes. If $y\%$ of the students changed their preference from the beginning to the end of the semester, what is the difference between the maximum and minimum possible values of $y$?
A) 20%
B) 30%
C) 40%
D) 50%
E) 60%

Present the answer in LaTex format: \boxed{Your answer}
user