Use an Insert operation to load data because the data is not already in Salesforce and does not need to be updated or deleted3. Map an External ID data value to the object because External IDs are used to create relationships between records that are being imported and records that already exist in Salesforce4. Reference: 3 https://help.salesforce.com/s/articleView?id=sf.data_loader_insert.htm&type=5 4 https://help.salesforce.com/s/articleView?id=sf.data_loader_relationships.htm&type=5

Two considerations that the administrator should remember about roll-up summary fields are:
Roll-up types include COUNT, SUM, and AVG. A roll-up type is a function that determines how the data from the child records is aggregated and displayed on the parent record. The available roll-up types are COUNT, which counts the number of child records; SUM, which adds up the values of a numeric field on the child records; AVG, which calculates the average value of a numeric field on the child records; MIN, which displays the lowest value of a field on the child records; and MAX, which displays the highest value of a field on the child records.
Roll-up summary fields are created on the master side of a master-detail relationship. A master-detail relationship is a type of relationship that links two objects together such that the master object controls certain behaviors of the detail object, such as security and deletion. A roll-up summary field is a type of field that displays a value that is calculated from child records related to a parent record. Roll-up summary fields can only be created on the master object of a master-detail relationship or on a lookup relationship if it is set as required.
The other two options are incorrect because:
Roll-up summary fields do not prevent the conversion of a master-detail relationship to a lookup. They only prevent it if they reference a formula field that includes another relationship.
Rollup fields are not calculated prior to save. They are calculated after save and may take some time to update.

To restore the deleted Review records, you need to restore both the Account and Product master records from the Recycle Bin. A master-detail relationship is a type of relationship that links two objects together and enforces a parent-child relationship between them. A master-detail relationship affects the security and deletion of the child records. If you delete a master record, all of its detail and subdetail records are deleted as well and moved to the Recycle Bin. To restore a detail or subdetail record, you must first restore its parent record. Reference: https://help.salesforce.com/s/articleView?id=sf.relationships_considerations.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.recyclebin_overview.htm&type=5