How can you overwrite the default input format? | Hadoop

A.  In order to overwrite default input format, the Hadoop administrator has to change default settings in config file.
B.  In order to overwrite default input format, a developer has to set new input format on job config before submitting the job to a cluster.
C.  The default input format is controlled by each individual mapper and each line needs to be parsed indivudually.
D.  None of these answers are correct.

Answer: B