Answer:
var birthday = "12/2/1978";
Step-by-step explanation:
It does not create a date object named birthday because in this statement the birthday is a string which contains 12/2/1978 a date it is not date object it is a string.All other three options are correct way to create a date object.
var birthday = new Date();
creates a date object with the current date and time.
we can also pass date string in the new Date().So var birthday = new Date("12/2/1978"); is also correct.
we can also pass year,month,day in new Date() In this order only.So option fourth is also correct.