Which of the following concatenates the contents of a string variable named city, a comma, a space, and the contents of a string variable named state and then assigns the result to a string variable named cityState? 

a. cityState = "city" + ", " + "state"; 

b. cityState = city + ", " + state; 

c. cityState = city & ", " & state; 

d. cityState = "city, + state";