Given the following main method:

What is the result?

Given the code fragment:

Which three code fragments are valid at line n1? (Choose three.)

You are developing a banking module. You have developed a class named ccMask that has a maskcc method.
Given the code fragment:

You must ensure that the maskcc method returns a string that hides all digits of the credit card number except the four last digits (and the hyphens that separate each group of four digits).
Which two code fragments should you use at line n1, independently, to achieve this requirement?

Given the code fragment:

What is the result?

Which two code fragments cause compilation errors? (Choose two.)