Bill Gates notices that his user interface intermittently stops responding to the mouse while it is downloading files in the background. Of the following techniques that he could be using to implement the background task, which could be responsible for this problem? (choose all good answers) I. II. heavy use of blocking I/O calls poor handling of idle time in the event loop poor choice of timeout in timers III. Select one: O a. II and Ill only O b. I, II and III O c. None O d. I only O e.I and II only