CCD-410 Warm-up

You have a large dataset of key value pairs, where the keys are strings and the values are the integers. For each unique key, you want to identify the largest integer. In writing a MapReduce program to accomplish this, can you take advantage of a combiner?

Given the following code from a MapReduce application:
Job job = new Job(getConf(), "MyMapReduceJob");
Path in = new Path(“source1”, “source2”);
Path out = new Path(“dest1”);
FileInputFormat.setInputPaths(job, in);
FileOutputFormat.setOutputPath(job, out);

Which one of the following statements is true?