You are developing a Windows Store app that will provide users with the ability to perform price
comparisons between online retailers.
You build a user interface (UI) that has a button. The button is used to perform the price
comparisons.
You write an event handler that contains the following code:

You need to ensure that once the button is clicked, the button is disabled until the comparison
completes. The solution must prevent the app from blocking access to the UI.
Which code segment should you insert at line 07?

A.
Option A

B.
Option B

C.
Option C

D.
Option D

Explanation:
http://msdn.microsoft.com/en-us/library/hh160374(v=vs.110).aspx