For this task you need to download twitter dataset from the link mentioned in 2). This time you have to answer query “what are the top 10 hashtags used in the given tweets”. To answer this you need to use MapReduce. You can look at the scheme of the collection using db.collection.findOne(). It will print one record with scheme information. Also you can use function like this.hasOwnProperty(‘field_name’) to check if a field exist in the record. (if the field does not exist you will get error.