Exam CRT-450 topic 1 question 69 discussion

Roll-Up summary doesn't have avg . Master detail gives access to both master and detail which is not desired here.

A. Create a trigger on the Rating object that updates a fields on the Employee object. B. Create a lookup relationship between the Rating and Employee object. Roll up summary doesn't have avg

A & D makes more sense. You can't have a rating without an employee. Tested in a Dev Sandbox when creating a master detail on a custom object to Employee object: "Sharing Setting - Select the minimum access level required on the Master record to create, edit, or delete related Detail records: Read Only: Allows users with at least Read access to the Master record to create, edit, or delete related Detail records. Read/Write: Allows users with at least Read/Write access to the Master record to create, edit, or delete related Detail records."

I think B is not best option because Rating object has no sense without Employee object. In MD only read access to the parent is obligatory for detail object. Create/Edit/Delete permissions can be separate for master and detail record.

I I would vote for A & D: A because as already explained by others there is no AVG function in roll-up summary fields. D because you just need read access to the parent to be able to create child records and, to me, it wouldn't make sense a rating record without an associated employee; of course you can enforce requirement for a lookup relationship but it could also be optional and in B it's not stated that the lookup relationship should be marked as required..

C cannot be correct since there is not AVE formula for roll-up field

There is no AVG in Roll-Up summary In a Master-Detail de detail inherit definitions access from Master.

And... if a Master-Detail relationship is used, and employees can create Ratings, then they'd also be able to create Employees.