Final answer:
When organizing names in an alphabetic filing system, P. Jansen would come first as it has the fewest characters before the first deviation in comparison to the other names listed.
Step-by-step explanation:
In alphabetic filing, names are generally organized by surname, followed by the given name and then the middle name or initial if they are provided. When considering variations of the same name with different initials, we file in order of the first deviating character, treating spaces as coming before any letter. Based on these guidelines:
- P. M. Jansen would come after any Jansen with just a first initial or no middle initial.
- P. Matthew Jansen would follow P. M. Jansen because full names follow initials.
- Paul Matthew Jansen would come after P. Matthew Jansen because full names follow initials.
- P. Jansen would come first as it has the fewest initials and no given name, making it the first deviating character compared to the others.
Therefore, the name P. Jansen would come first in an alphabetic filing system.