Q: What channel is not included in the default Channels report?
A) Organic Search
Correct Answer is D) Device.
The default system channel definitions reflect Analytics’ current view of what constitutes each channel in the Default Channel Grouping.
Default channels are Direct, Organic Search, Social, Email, Affiliates, Referral, Paid Search, Other Advertising and Display.
Read more here: https://support.google.com/analytics/answer/3297892