When loading data into an operation, what can a developer do to match records to update existing records? (Choose 2)

When loading data into an operation, what can a developer do to match records to update existing records? (Choose 2)
A . Match an auto-generated Number field to a column in the imported file.
B . Match an external Id Text field to a column in the imported file.
C . Match the Name field to a column in the imported file.
D . Match the Id field to a column in the imported file.

Answer: B, D