Combiner mode attempts to distribute huge skewed-key value sets to several vertices that support concurrent execution of the work. There are various attributes of combiner mode? What is the meaning of SqlUserDefinedCombiner(Mode=CombinerMode.Inner).

Answer options:

A.Every output row potentially depends upon all the input rows from left and right with the same key value.
B.Every output row depends upon a single input row from the left (and potentially all rows with the same key value from the right).
C.Every output row depends upon a single input row from the right (and potentially all rows with the same key value from the left).
D.Every output row depends upon a single input row from the left and the right with the same value.
E.None of these

Correct Answer: D 
The following are the attributes of the combiner mode: 

Option A is incorrect. This is the description for SqlUserDefinedCombiner(Mode=CombinerMode.Full).
Option B is incorrect. This is the description for SqlUserDefinedCombiner(Mode=CombinerMode.Left).
Option C is incorrect. This is the description for SqlUserDefinedCombiner(Mode=CombinerMode.Right).
Option D is correct. This is the description for SqlUserDefinedCombiner(Mode=CombinerMode.Inner).
Option E is incorrect. D is the right answer.
Reference: 
To know more about Resolve data-skew problems, please visit the below link: 

https://docs.microsoft.com/en-us/azure/data-lake-analytics/data-lake-analytics-data-lake-tools-data-skew-solutions