existSpark, assuminglinesIs anDStreamobject, which of the following statements can periodically count this number of words...

lines.flatMap(_.split(" ")).map(word =>(word,1)).reduce(_+_).print( )

lines.flatMap(_.split(" ")).map(word =>(word,word.length())).reduceByKey

(_+_).print( )

lines.flatMap(_.split(" ")).map(word =>(word,1)).reduceByKey(_+_).print

( )

lines.flatMap(_.split(" ")).flatmap(word =>(word,1)).groupByKey(_+_).print

( )