The correct answer is: B. Calculated field
A calculated field is a field that displays the results of a calculation based on the values in other fields. For example, you could create a calculated field that displays the total sales for each product by multiplying the quantity sold by the unit price.
A lookup field is a field that displays the value from another table based on the value in the current table. For example, you could create a lookup field that displays the name of the customer who placed an order based on the order number.
A source field is a field that contains the original data. For example, if you have a table of customers, the customer name field would be a source field.
A child field is a field that is related to a parent field. For example, if you have a table of orders, the order number field would be a parent field and the order date field would be a child field.
I hope this helps!