You will be given a definition of a task first, then some input of the task.
In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

[header] How to download microsoft office 2010 [title] Visit the office 2010 download page. [step] Microsoft office can be legally downloaded from microsoft's website as long as you have a valid 25-character product key. To find it easily, search for " using your office 2010 product key ". <sep> (A) [substeps] If you don't have a csso account, you may have to create one. You will need to verify your identity with microsoft office 2010. (B) [substeps] Office 2010 is no longer available for purchase or as a trial from microsoft. You can still buy boxed copies from other retailers. (C) [substeps] Leave one or more lines between the tabs on the homepage and the window you will be downloading to provide information about what you want to download. [title] Open the primary file you wish to download. (D) [title] Enter the windows code to install microsoft office 2010. [title] Click on the save file to run the pc then re-open microsoft office 2010 now to continue.
Output:
B