What is the correct format in JSON, should I quote names also?

Question

I am writing a JSON file, but I am not sure about which of the following formats is the correct one?

Quoting variable names and all string values

{
    "class": {
        "number": 2,
        "student": {
            "name": "Tom",
            "age": 1
        },
        "student": {
            "name": "May",
            "age": 2
        }
    }
}

or

Quoting only string values

{
    class: {
        number: 2,
        student: {
            name: "Tom",
            age: 1
        },
        student: 
        {
            name: "May",
            age: 2
        }
    }
}  

Answer 1

The first is valid, if you're unaware you can validate your JSON output online pretty easily here: http://www.jsonlint.com/