Which of the following would be an example of a variable declaration?

The correct answer is a clear example of variable declaration in the context of programming. When using the keyword "var," you are explicitly declaring a variable named "myVariable" and assigning it the value of 10. This follows the syntax of many programming languages, including JavaScript, where declaring a variable sets aside a specific location in memory to store the value of the variable.

In general, a variable declaration is meant to introduce and define a variable, which allows it to be used later in the code. The syntax used in this case adheres to standard constructs in programming, demonstrating the fundamental concept of how to create a variable.

The other choices do not represent valid variable declarations within this context. For example, "let myVar = 'Hello';" is also a valid declaration but uses a different keyword for declaring variables, which could lead to confusion if looking strictly for the example that was asked. The statement "define myVariable as 10;" lacks the proper syntactical structure common in programming languages, making it invalid. Similarly, the phrase "set myVariable = 'Hello';" isn't a declaration but instead an assignment operation without introducing the variable first.