how to create a d3.js tree using mvc 4 with json

how to create a d3.js tree using mvc 4 with json

I want to create a d3.js tree in mvc 4 using code first database using
json, i want my result of json in form of
**
var treeItem = "name": "A", "children": [ { "name": "A1" }, { "name": "A2"
}, { "name": "A3", "children": [ { "name": "A31", "children": [ { "name":
"A311" }, { "name": "A312" } ] }] } ] };
**
Please help me to do this task...i am really helpless this time