Which of the following could work using Pymongo to project just the
`student_id` from the scores collection using a find command?

1) cursor = students.find( { }, { student_id : 1, _id : 0 } )

2) cursor = students.find( { }, { 'student_id' : 1, '_id' : 0 } )

3) cursor = students.find( { 'student_id' : 1 } )

4) cursor = students.find( { 'student_id' : 1, '_id' : 0 } )