To ensure that the TestUtils class and its methods are only accessible by unit test methods, the class must be annotated with the @isTest annotation. This annotation limits the scope of the class and its methods to test contexts only.
Why @isTest?
Purpose of @isTest:
The @isTest annotation marks a class or method for use exclusively within test scenarios. It prevents the methods from being accidentally invoked in production code.
This ensures better test isolation and prevents misuse.
Static Test Data Methods:
Marking helper methods for test data creation as @isTest ensures they do not interfere with production code and are strictly for testing purposes.
Analysis of Options:
Option A: @isTest above line 03:
Incorrect. Applying @isTest only to the createAccount method would work, but the other methods in the class would still be accessible. This does not satisfy the requirement of restricting the entire class.
Option B: Add @isTest above line 01:
Correct. Annotating the class ensures all methods within the class are accessible only in the context of tests.
Option C: Change public to private on line 01:
Incorrect. Changing the class to private would cause a compilation error, as top-level classes in Salesforce cannot be declared private.
Option D: Remove static from line 03:
Incorrect. Removing static does not affect the test scope of the class or its methods. Static methods can still be invoked, and this does not restrict access to test contexts.
Correct Implementation:
The corrected code would look like this:
@isTest
public class TestUtils {
public static Account createAccount() {
Account acct = new Account();
// Set some fields on acct
return acct;
}
// Other methods...
}
References:
Apex Testing: Test Classes and Methods
Trailhead Module on Apex Testing

The best way to declare maxAttempts to meet the requirements is to declare it as a private static variable on a helper class. This will ensure that the variable is initialized only once per Apex transaction, and that its value is preserved and shared across trigger executions. A private static variable is a variable that belongs to a class and not an instance, and that can only be accessed within the class. A helper class is a class that contains common methods or variables that can be used by other classes or triggers.
References: The use of private static variables and helper classes can be referenced in the Salesforce Platform Developer I learning documents, specifically in modules that cover Apex basics and triggers, such as:
* Apex Basics & Database
* Apex Triggers
* Apex Testing