Which of the following file formats is used for exchanging amateur radio log data?
Why ADIF stands for Amateur Data Interchange Format, the standard text-based file format logging programs use to exchange QSO records. It lets you move contacts between logging software, upload to Logbook of the World or eQSL, and merge logs after a contest without retyping. Each record is a series of tagged fields such as <CALL>, <BAND>, <MODE> and <QSO_DATE>.
Watch out NEC is the Numerical Electromagnetics Code used for antenna modeling, ARLD is the prefix on ARRL DX news bulletins, and OCF refers to an off-center-fed dipole antenna, none of which have anything to do with log files.
ADIF = Amateur Data Interchange Format. The only choice with 'D' for Data in it.