didn’t work convert json decoded string to array in php which is send by ajax method

i have js object

data=[{'quest':'sometext'},{'option':['a','b', 'c']}, {'cor':[0,1,0]},{'sol':'again tetx'}]

Submited as ajax data using jquery

... data:{'qs':JSON.stringify(data)}, ...

i recieved the as post and try to convert to array

$array=json_decode(json_encode($_POST['qs']), true);

but output is

print_r($array); \is

[{"quest":"sometext"},{"option":["a","b", "c"]}, {"cor":[0,1,0]},{"sol":"again tetx'}]

i want to make it array in php