现有以下语句:val array=Array("Hadoop is good", "Spark is fast", "Spark is better");val lines=sc.papallelize(array)val words=lines.flatMap(1ine=>line.split(""))上述语句执行以后,words中的元素是( )
选项：

A:"Hadoop is good","Spark is fast", "Spark is better"
B:"Spark","is","fast"
C:"Hadoop","is","good","Spark","is","fast","Spark","is","better"
D:"Hadoop","Spark","fast"