What is the recommended way to avoid locking issues during import?

A customer is facing locking issued when importing large data volumes of order records that are children in amaster-detail relationship with the Account object.

What is the recommended way to avoid locking issues during import?
A . Import Account records first followed by order records after sorting order by OrderID.
B. Import Account records first followed by order records after sorting orders by AccountID.
C. Change the relationship to Lookup and update the relationship to master-detail after import.
D. Import Order records and Account records separately and populate AccountID in orders using batch Apex.

Answer: B