【单选题】val pairRDD1 = sc. parallelize(Array(("spark",1),("spark",2),("hadoop",3),("hadoop",5))) val pairRDD2 = sc.parallelize(Array(("spark","fast"))) pairRDD1.join(pairRDD2) 上述语句执行以后, pairRDD1 这个 RDD 中所包含的元素是
A: (“spark”,(1,”fast”)), (“spark”,(2,”fast”))
B: (“hadoop”,(2,”fast”)), (“hadoop”,(1,”fast”))
C: (“hadoop”,(3,”fast”)), (“hadoop”,(5,”fast”))
D: (“spark”,(3,”fast”)), (“spark”,(5,”fast”))