Given the string variable "invoiceNumber = 'INV 1432'", which expression would replace the last four digits with "1526"?

The correct expression to replace the last four digits of the string "invoiceNumber = 'INV 1432'" with "1526" is based on the use of the string manipulation methods available in many programming languages.

The choice that utilizes the Replace method effectively substitutes the specific substring found in the original string. In this case, the method invoiceNumber.Replace("1432", "1526") takes two arguments: the first is the substring you want to find ("1432"), and the second is the new substring you want to replace it with ("1526"). This operation successfully modifies the existing string to produce "INV 1526", directly targeting the part of the string that needs changing.

The other options either misuse the string manipulation functions or do not conform to the standard syntax or expect input types, thereby making them ineffective for this specific requirement. Understanding string manipulation in programming involves knowing how to properly find and replace substrings, ensuring you use the correct methods and parameters for your specific programming language.