To process input key-value pairs, your mapper needs to lead a 512 MB data file in memory. What is the best way to accomplish this? 

Serialize the data file, insert in it the JobConf object, and read the data into memory in the configure method of the mapper. 

Place the data file in the DistributedCache and read the data into memory in the map method of the mapper. 

Place the data file in the DataCache and read the data into memory in the configure method of the mapper. 

Place the data file in the DistributedCache and read the data into memory in the configure method of the mapper.