A company has a model-driven app with the rollup field of the "Total estimated revenue" of open opportunities for the account. The company wants to recalculate the value of this column whenever open opportunities change in a system. Therefore, it is considering using an API call to CalculateRollupField Function. The function takes the table name, the record identifier, and a column name. The company invites you to design and implement the solution. 
What two items will you use in your design to update the rollup field?

Answer options:

A.Azure Function
B.Power Automate
C.Webhook
D.Custom connector
E.Azure Service Bus

Correct Answers: B and D 
Microsoft Dataverse provides special column types for calculations and data aggregation. These types are Calculation and Rollup. The Calculation column allows users to define a formula based on the column value. This type includes columns from the same table and related parent table in a many-to-one relationship. Calculated columns are read-only. Users benefit from a list of built-in functions for the calculated values and operate on the different data types like text, numeric, and date-time. The calculations run synchronously when a record is saved. 
The Rollup column is like the Calculated type. They operate only with the numeric (Whole Number, Decimal Number, and Currency) and date-time datatypes. The Rollup type includes columns from the same table and related child tables in a one-to-many relationship. The list of built-in functions for the Rollup column is smaller compared to the Calculated columns. It includes sum, min, max, and count. Rollup columns are read-only. By default, the calculations for the Rollup column run once per hour. Users can change the frequency in Customization settings for the table, but the minimum is one hour. It is an asynchronous operation. 
Suppose you need to update a rollup column when some related rows are updated. Dataverse provides an API CalculateRollupField function that can calculate the column on demand. You need to create a custom connector with the call to this API function and use this connector with Power Automate flow. In Power Automate, you create an automated flow triggered by the Dataverse "When a row is added, modified or deleted" and calling the custom connector with table and column parameters. The custom connector calls the function. And the function will update the rollup column. 
All other options are incorrect. 
For more information about The Dataverse rollup columns, please visit the below URLs: 

https://docs.microsoft.com/en-us/learn/modules/data-modeling/5-dataverse
https://docs.microsoft.com/en-us/learn/modules/create-define-calculation-rollup-fields/2-rollup
https://docs.microsoft.com/en-us/powerapps/maker/data-platform/define-rollup-fields
https://silicium-consulting.com/en/tutorial-automatically-calculate-rollup-fields-using-power-automate/