Which line of code should you use?

You are testing the value of the following variable in JavaScript.
var height = “300”;
A block of code must execute if the following conditions are true:
The height variable is set to 300
The height variable is of type string
You need to implement the code to run the test.
Which line of code should you use?

A.
if (height = = 300)

B.
if (height = = “300”)

C.
if (height ! “300”)

D.
if (height ! = 300)

Explanation:

Use = = to test for equality.
Use “300” to test for the string.