C line of code is not compiling properly

Tell us what’s happening:

Your code so far

// Only change code below this line
var a = 5;
var b = 10;
var c = "i am a";
// Only change code above this line

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

Please i want to move forward in my lesson can someone tell me whats wrong with this code

Challenge: Understanding Uninitialized Variables

Link to the challenge:

i am a String! is not the same as I am a String!

coding is case sensitive