Catchphrase jobs quiz

Can you guess the occupation connection from the catchphrase clue ?
?
1.
job1
2.
job2
3.
job3
4.
job4

  1. Master of Ceremonies
1 Like
  1. Personal Trainer
1 Like
  1. Bachelor Degree
1 Like
  1. Personal Trainer … Correct
  2. Master of Ceremonies … Correct
    4 Bachelor Degree … Correct

3
image

do not think anyone can guess this last one needed here so will give the answer

3 Dewey Decimal System , Correct

i had never heard of that type of job so google is my friend and this is what it says
Dewey Decimal System, is a proprietary library classification system which allows new books to be added to a library in their appropriate location based on subject.