Created the first exercise of the listening demo

src/demo/listening.json

@@ -0,0 +1,64 @@
+{
+  "audio": {
+    "title": "",
+    "source": "",
+    "transcript": "",
+    "repeatableTimes": 3
+  },
+  "exercises": [
+    {
+      "type": "multipleChoice",
+      "prompt": "Select the appropriate option",
+      "questions": [
+        {
+          "id": "1",
+          "prompt": "What does her briefcase look like?",
+          "solution": "A",
+          "variant": "image",
+          "options": [
+            {
+              "id": "A",
+              "src": "https://i.imgur.com/sU7SLvF.png"
+            },
+            {
+              "id": "B",
+              "src": "https://i.imgur.com/i5RacYK.png"
+            },
+            {
+              "id": "C",
+              "src": "https://i.imgur.com/rEbrSqA.png"
+            },
+            {
+              "id": "D",
+              "src": "https://i.imgur.com/2lZZ9kM.png"
+            }
+          ]
+        },
+        {
+          "id": "2",
+          "prompt": "What did she have inside her briefcase?",
+          "solution": "D",
+          "variant": "text",
+          "options": [
+            {
+              "id": "A",
+              "text": "wallet, pens and novel"
+            },
+            {
+              "id": "B",
+              "text": "papers and wallet"
+            },
+            {
+              "id": "C",
+              "text": "pens and novel"
+            },
+            {
+              "id": "D",
+              "text": "papers, pens and novel"
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}