Understanding Uninitialized Variables (Test pass but can not go to next challenge)

What is the mistake in following code it can not pass the test

Your code so far

var a = 6;
var b = 15;
var c = "I am a String!";

** Tried with following as well **

var a = 5;
var b = 10;
var c = "I am a";

a= a+1;
b = b +5;
c = c + " String!";

console output is as follows:

// running tests
Do not change code below the line
// tests completed

Your browser information:

User Agent is: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36.

Link to the challenge:

You changed the code below the line… this is not how they were written originally

If you reset code I think it will be faster for you

Respect the

// Do not change code below this line

Thanks buddy i haven’t care about that i will do for next challenges