From the below code. what is the most appropriate next step in ML process?
val uniionRatingsRDD = ratingsRDD.union(newRatingsRDD)
val model = (new ALS.setRank(20).setIterations(10).run(unionRatingsRDD))
1. val predictionsForTestRDD = model.predict(ratingsRDD)
2. val model = ratingsRDD.split(userid,20)
3.val splits = ratingsRDD.randomSplit(Array(0.8,0.2),0L)
4. val topRecsForUser = model.recommendProducts(userid,5)