在Spark应用开发中,以下哪项的代码能正确进行单词统计?()
A. valcounts=textFile.map(line=>line.split(“”)).map(-rd=>(word,1)).reduceByKey(_+_)
B. valcounts=textFile.flatMap(line=>line.split(“”)).map(word=>(word,1)).reduceByKey(_+_)
C. valcounts=textFile.map(line=>line.split(“”)).map(word=>(word,1)).groupByKey(_+_)
D. valcounts=textFile.flatMap(line=>line.split(“”)).map(word=>(word,1)).groupByKey(_+_)