Hello @Yunus_UYANIK, welcome to the MongoDB Community forum!
The link you had provided (and referred above) is for the explain database command.
The exam is referring to the db.collection.explain method. The documentation says the same thing as that of the exam problem’s answer. The
verbosity parameter description:
Optional. Specifies the verbosity mode for the explain output. The mode affects the behavior of explain() and determines the amount of information to return. The possible modes are: