docs: add design challenges for karaoke exercises type

lal-api-design.md

@@ -1,7 +1,8 @@
 
 # 📘 LAL Project API – Exercises Endpoint
 
-This document describes the API endpoints for managing exercises within a lesson in the LAL (Learn Arabic Language) project. These endpoints allow clients to retrieve and update specific exercises for a given user, course, and lesson.
+This document describes the API endpoints for managing exercises within a lesson in the LAL (Learn Arabic Language) project.\
+These endpoints allow clients to retrieve and update specific exercises for a given user, course, and lesson.
 
 **_NOTE: this is a work-in-progress API specification for the LAL (Learn Arabic Language) project._**
 ---
@@ -71,4 +72,31 @@ Modifies an existing exercise and its tasks.
     }
   ]
 }
-```
+```
+
+### Exercise Type Karaoke Audio Design Challenges
+
+Before providing the API specs for the second type of the exercises page, there's some design challenges related to handling audio files in the API response we should take into consideration.
+
+---
+
+##### Design Challenge 1: Base64 Encoding of Audio
+
+**Problem:** How to include audio in the API response.  
+**Option:** Encode the audio as a Base64 string in the JSON.
+
+---
+
+##### **Design Challenge 2: Referencing Audio by Path/URL**
+
+**Problem:** How to reference audio in the API response.  
+**Option:** Store the audio externally and include the file path or URL in the JSON.
+
+---
+
+##### **Design Challenge 3: Hybrid Approach**
+
+**Problem:** Flexibility in handling audio.  
+**Option:** Provide both a file path and Base64-encoded audio in the JSON.
+
+---