Your company has an e-commerce website that will have 1000s of users per hour. You are setting up a stream data processing solution backed by Azure stream analytics. The marketing team will use this data for detailed analysis.You are writing a query that will send active users` data on the website for the last20 seconds. This should be separate based on the page they visited. Choose the option which matches your query the most.

Answer options:

A.SELECT productid, location(*) AS Count FROM websitevisitors TIMESTAMP BY CreatedAt GROUP BY Page, TumblingWindow(second, 10)
B.SELECT productid, location(*) AS Count FROM websitevisitors TIMESTAMP BY CreatedAt GROUP BY Page, SessionWindow(second, 10)
C.SELECT productid, location(*) AS Count FROM websitevisitors TIMESTAMP BY CreatedAt GROUP BY Page, HoppingWindow(second, 10)
D.SELECT productid, location(*) AS Count FROM websitevisitors TIMESTAMP BY CreatedAt GROUP BY Page, SnapshotWindow(second, 10)

Correct Answer: A
If you look at the options, you can find that only the window function is changing. It is mentioned in the question that the data should be collected for an interval of 20 seconds and should be grouped by page. All the options contain grouping by page. So, finding the function type which collects stream data and changes into the time segments and does the function will be the right answer. This is basically the functionality of the Tumbling window function.
Option A is correct: Tumbling function does this as the explanation says.
Option B is incorrect: This functions will output events only for points in time when there is a change in the content in the selected window.
Option C is incorrect: These types of functions hop forward in time by a constant period.
Option D is incorrect: It just groups the events based on timestamp and doesn’t require specific value as input for window function.
Reference: 
To know more about Window Functions, please refer to the doc below: 

https://docs.microsoft.com/en-us/azure/stream-analytics/stream-analytics-window-functions