What should you do before you can create the relationship?

You need to create the required relationship for the executive’s visual.

What should you do before you can create the relationship?
A . Change the data type of Sales[region_id] to Whole Number.
B . In the Sales table, add a measure for sum(sales_amount).
C . Change the data type of sales[sales_id] to Text.
D . Change the data type of sales [region_id] to Decimal Number.

Answer: C