Which method is used to convert a string to uppercase?

The method used to convert a string to uppercase is accurately identified as ToUpper. This method is commonly available in various programming languages, such as C# and Java, as part of their string manipulation libraries. When you call ToUpper on a string, it processes each character in that string and transforms all lowercase letters to their uppercase equivalent, while leaving other characters unchanged. This is a standard function utilized in text processing and formatting, making it an essential tool for developers when they need to ensure that string data adheres to specific casing conventions.

Other options, while they might sound plausible, do not reflect the actual naming conventions used in programming languages for this functionality. For example, ToUpperCase is a variation that is not typically used in major programming environments. ChangeCase and UpperCase may resemble related functions or concepts but do not represent any established method for converting strings to uppercase in the most widely used programming languages.