The correct answer is: B. inputsplit
An input split is a logical division of the input data set. It is used to determine the number of map tasks that will be created for a job. The InputFormat class is responsible for generating input splits.
An output split is a physical division of the output data set. It is used to determine the number of reduce tasks that will be created for a job. The OutputFormat class is responsible for generating output splits.
An input split stream is a stream of input splits. It is used to read the input data set and generate input splits. The InputSplitIterator class is responsible for generating input split streams.
Therefore, the correct answer is B. inputsplit.