Explanation
The reason why there are many duplicate Account records and numerous sharing rules created in Salesforce is that the Organization-Wide Default for the Account object is Private4. This means that users can only see their own accounts and those shared with them explicitly by sharing rules or other means. This could lead to users creating duplicate accounts without knowing that they already exist in Salesforce. If the Organization-Wide Default for the Account object is Public Read/Write or Public Read Only, users would be able to see all accounts in Salesforce and avoid creating duplicates. The Object permissions for the Account object are not relevant for this question.

Explanation
Order, Asset, and Contact are the three objects that can be configured as "Controlled by Parent" in Sharing Settings when Person Account is enabled in a Salesforce organization. Controlled by Parent means that the sharing setting for the object is determined by the parent record. For example, an order's sharing setting is determined by its associated account. Opportunity and Case are not objects that can be configured as
"Controlled by Parent" in Sharing Settings.

Explanation
Creating a Permission Set that grants "View All" permission for Opportunity is the best approach to meet the requirements. This will allow the Sales Reporting team to view all Opportunity records without changing their profile or OWD settings. Creating a Permission Set that grants "View All Data" permission would give them access to all data in the org, which is not necessary. Making Opportunity OWD read-only would affect all users in the org, which may not be desirable. Giving "View All Data" permission to the Sales Reporting Profile would also give them access to all data in the org, which is not necessary