What will be the output of a complete program if there are no syntax errors?

The choice indicating that the program will run successfully and output its messages is correct because it highlights the expected result of a properly functioning program. When a program executes without any syntax errors, it means that the code has been written in accordance with the language's grammatical rules, allowing it to be parsed correctly by the compiler or interpreter.

In this scenario, assuming the program contains logical statements that execute and produce output, the program will carry out its intended operations and display the output as designed by the programmer. This could include printing messages to the console, performing calculations, or any number of tasks that have been programmed into the code.

The other possibilities, such as outputting nothing, displaying an error message, or crashing, would arise only if there were issues beyond syntax errors, such as logical errors or runtime exceptions. However, under the condition stated—having no syntax errors—the expectation is that the program will run successfully and produce the specified output.