How can I retrieve and capture Adaptive card action.submit

Question

I have created a LUIS Template Bot Application (Version 3) and I need to capture the output of an Adaptive Card drop down list. I am currently able to create and render the drop down list but facing difficulty capturing the result once the button is clicked. Can you please give me a solution or give link to appropriate tutorial for version 3 as resources for this issue is mostly for version 4.

 

public Attachment PolicyAdaptiveCard() {
 var card = new AdaptiveCard();
 var choices = new List < AdaptiveChoice > ();
 choices.Add(new AdaptiveChoice() {
  Title = "Category 1", Value = "c1"
 });
 choices.Add(new AdaptiveChoice() {
  Title = "Category 2", Value = "c2"
 });
 var choiceSet = new AdaptiveChoiceSetInput() {
  IsMultiSelect = false, Choices = choices, Style = AdaptiveChoiceInputStyle.Compact, Id = "Category"
 };
 card.Body.Add(choiceSet);
 card.Actions.Add(new AdaptiveSubmitAction() {
  Title = "Select Category", Data = Newtonsoft.Json.Linq.JObject.FromObject(new {
   button = "select"
  })
 });
 Attachment attachment = new Attachment() {
  ContentType = AdaptiveCard.ContentType, Content = card, Name = $ "Card"
 };
 return attachment;
}

This is JSON output that I am capturing in Bot Emmulator

{
"channelData":{
"clientActivityID":"15547009411880.yfus2yy2mao",
"postBack":true
},
"channelId":"emulator",
"conversation":{
"id":"3f50f7c1-59be-11e9-98bd-17dcaa70e8d3|livechat"
},
"from":{
"id":"r_tckd4zoa8h",
"name":"User",
"role":"user"
},
"id":"48d27080-59be-11e9-93ff-a77a4eb2d000",
"localTimestamp":"2019-04-08T08:22:21+03:00",
"locale":"en-US",
"recipient":{
"id":"97e06f60-496a-11e9-9541-3d37a55e03cc",
"name":"Bot",
"role":"bot"
},
"serviceUrl":"http://localhost:56373",
"showInInspector":true,
"timestamp":"2019-04-08T05:22:21.192Z",
"type":"message",
"value":{
"Category":"c1",
"button":"select"
}
}

How can I read the value and output "c1" in the next method ? This is the code that I am following. Can you please give me the method I can use to capture the category value

var reply = context.MakeMessage();
var activityValue = context.Activity.AsMessageActivity().Value as Newtonsoft.Json.Linq.JObject;
if (activityValue != null) {
 var categorySelection = activityValue.ToObject < CategorySelection > ();
 var category = categorySelection.Category;
 await context.PostAsync(reply);
}