Which DAX expression should you use to get the ending balances in the balance sheet reports?

You need to design the data model and the relationships for the Customer Details worksheet and the Orders table by using Power BI. The solution must meet the report requirements.
For each of the following statement, select Yes if the statement is true, Otherwise, select No.
NOTE: Each correct selection is worth one point.

You have a folder of monthly transaction extracts.
You plan to create a report to analyze the transaction data.
You receive the following email message: "Hi. I've put 24 files of monthly transaction data onto the shared drive. File Transactions201901.csv through Transactions201912.csv have the latest set of columns, but files Transactions201801.csv to Transactions201812.csv have an older layout without the extra fields needed for analysis. Each file contains 10 to 50 transactions." You get data from the folder and select Combine & Load. The Combine Files dialog box is shown in the exhibit. (Click the Exhibit tab.)
For each of the following statements, select Yes if the statement is true. Otherwise, select No.
NOTE: Each correct selection is worth one point.

You are creating a Microsoft Power Bl model that has two tables named CityData and Sales. CityData contains only the data shown in the following table.
Sales contains only the data shown in the following table.
For each of the following statements, select Yes if the statement is true. Otherwise, select No.
NOTE: Each correct selection is worth one point.

You are developing a sales report that will have multiple pages. Each page will answer a different business question.
You plan to have a menu page that will show all the business questions.
You need to ensure that users can click each business question and be directed to the page where the question is answered. The solution must ensure that the menu page will work when deployed to any workspace.
What should you include on the menu page?