正则表达式获取Script中的Json字符串

正则表达式获取Json字符串
<script type="text/javascript" src="/retail/retail-static/xx/scripts/ac-globalfooter.built.js"></script>
<script id="__NEXT_DATA__" type="application/json">
    {"props":{members:{
        "Name":"_test".
        "Age":30,
        "HeadUrl":"http://www.baidu.com"
    }},
    "a":"123",
    "b":"123",
    "c":"123"}
</script>
<script type="text/javascript" src="/retail/retail-static/xx/scripts/ac-globalfooter.js"></script>

我希望使用正则表达式获取<script id="__NEXT_DATA__" type="application/json"></script>中的json对象。我用的是C#。辛苦大家，麻烦大神了。