In the reducer, the MapReduce API provides you with an iterator over Writable values. What does calling the next () method return?

• A. It returns a reference to a Writable object from an object pool.
• B. It returns a reference to the same Writable object if the next value is the same as the previous value, or a new Writable object otherwise.
• C. It returns a reference to a different Writable object time.
• D. It returns a reference to the same Writable object each time, but populated with different data.
• E. It returns a reference to a Writable object. The API leaves unspecified whether this is a reused object or a new object.

Which one of the following statements describes the relationship between the NodeManager and the ApplicationMaster?

• A. The ApplicationMaster starts the NodeManager in a Container
• B. The ApplicationMaster starts the NodeManager outside of a Container
• C. The NodeManager creates an instance of the ApplicationMaster
• D. The NodeManager requests resources from the ApplicationMaster

Given a directory of files with the following structure: line number, tab character, string:
Example: 1abialkjfjkaoasdfjksdlkjhqweroij 2kadfjhuwqounahagtnbvaswslmnbfgy 3kjfteiomndscxeqalkzhtopedkfsikj
You want to send each line as one record to your Mapper. Which InputFormat should you use to complete the line: conf.setInputFormat (____.class) ; ?

• A. SequenceFileInputFormat
• B. KeyValueFileInputFormat
• C. BDBInputFormat
• D. SequenceFileAsTextInputFormat

You want to perform analysis on a large collection of images. You want to store this data in HDFS and process it with MapReduce but you also want to give your data analysts and data scientists the ability to process the data directly from HDFS with an interpreted high-level programming language like Python. Which format should you use to store this data in HDFS?

• A. JSON
• B. SequenceFiles
• C. HTML
• D. XML
• E. Avro
• F. CSV