What does the third line below do? 18. double salary: String input: salary Double.parseDouble(input ) changes a String value into a Double value adds input to salary is syntax error d. a. b. . is run time error 19. The scope of variables declared (defined) in the main method are: known throughout the class b. a. known in all methods known throughout the package d. know only in the main method C. 20. A method that returns no value must be declared as: static . void . complex . d. one way A switch statement mixes or switches one or more variables lets the value of variable or expression determine where the program will branch to 21. a. b. cannot have a default outcome C. can only be used in the main method d. What Java keyword makes a value unchangeable (constant) during program execution? 22. const a. final b. permanent d. fixed C. 23. Which one of the follow are nat a valid assignment statement? a. total 9+ 2; 72 amount + 1; profit 129-19; myCharacter W; b. . d.