MyDownloadTask class in the following program implements a barebones asynchronous task for downloading a video file from a remote source. However,

there are some errors in the parameters and return types.

My DownloadTask class in the following program implements a barebones asynchronous task for downloading a video file from a remote source. However, there are some errors in the parameters and return types. class MyDownloadTask extends AsyncTask { protected void onPreExecute() { } protected Integer do InBackground (Void...arg) { return result; } protected void on ProgressUpdate (Integer...a) { } protected void on PostExecute (String result) { } } a) Identify those errors and correct them. b) Which methods in the code given below are optional? Which methods are run in the main thread