Which of the following are often used to ensure that data has been accurately input to the computer?

The correct answer is D. input controls.

Input controls are procedures or techniques used to verify the accuracy and completeness of data entered into a computer system. They can be used to prevent errors from occurring, or to detect and correct errors that do occur.

There are many different types of input controls, but some of the most common include:

• Check digits: A check digit is a digit that is added to a number to verify its accuracy. The check digit is calculated using a mathematical formula, and it is used to ensure that the number has not been entered incorrectly.
• Field validation: Field validation is a technique that is used to verify that data entered into a field is of the correct type and format. For example, a field that is supposed to contain a date might be validated to ensure that the date is in the correct format (e.g., MM/DD/YYYY).
• Range checking: Range checking is a technique that is used to verify that data entered into a field is within a specified range. For example, a field that is supposed to contain a number might be validated to ensure that the number is between 0 and 100.
• Existence checking: Existence checking is a technique that is used to verify that data entered into a field exists in a database. For example, a field that is supposed to contain a customer name might be validated to ensure that the customer name exists in the customer database.
• Recalculation: Recalculation is a technique that is used to verify that the results of a calculation are correct. For example, a field that is supposed to contain the total of a purchase might be recalculated to ensure that the total is correct.
• Echoing: Echoing is a technique that is used to verify that data entered into a field is what the user intended to enter. The data that is entered into the field is displayed back to the user, and the user is asked to verify that the data is correct.

Input controls are an important part of any computer system. They help to ensure that data is entered accurately and completely, and they can help to prevent errors from occurring.