Exam 70-779 topic 1 question 19 discussion

Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is the same in each question in this series.
Start of repeated scenario.
You are creating reports for a car repair company. You have four datasets in Excel spreadsheets. Four workbook queries load the datasets to a data model. A sample of the data is shown in the Data Sample exhibit. (Click the Exhibit button.)
Data Sample exhibit:




The data model is shown in the Data Model exhibit. (Click the Exhibit button.)

The tables in the model contain the following data:
✑ DailyRepairs has a log of hours and revenue for each day, workshop, and repair type. Every day, a log entry is created for each workshop, even if no hours or revenue are recorded for that day. Total Hours and Total Revenue column.
✑ Workshops have a list of all the workshops and the current and previous workshop managers. The format of the Workshop Manager column is always
Firstname Lastname. A value of 1 in the IsLatest column indicates that the workshop manager listed in the record is the current workshop manager.
✑ RepairTypes has a list of all the repair types
✑ Dates has a list of dates from 2015 to 2018
End of repeated scenario.
When you attempt to create a relationship between DailyRepairs and Workshops, Power Pivot generates the following error message: "The relationship cannot be created because each column contains duplicate values. Select at least one column that contains only unique values".
You need to ensure that you can create a valid relationship between the tables.
What should you do?