For the given instances (i.e. snapshot/subset) of a student relation, identify the following attributes (set) as might be a key or definitely not a key, and provide explanations. 1. name 2. sid 3. gpa 4. {name, login} Answer the following questions: Hint: Recall the definition of a candidate key and that this is simply a snapshot of the relation and may not include all records. 5) List all single attributes that are definitely not candidate keys. Why are these attributes definitely not candidate keys? If all attributes could be candidate keys, explain why. 6) Which single attribute is definitely a candidate key? Why? If there are no candidate keys, explain why. sid name login age gpa 23300 Amber amber@cs 19 3.3 13434 Joanna joanna@cs 18 3.4 5312 Smith smith@ee 18 3.2 5360 Smith smith@math 19 3.8 53231 Madayan mad@music 23 2.8 43232 Guldu guldu@ee 21 2.0