The idea of pairing each member of the domain with each member of the range referred to as mapping.
The figure shows a mapping of the elements of the domain to the elements of the range. Each element in the domain is increased by 1 to get the corresponding element in the range.
Correct Answer: B
Step 1: Draw the mapping diagram for the given relation.
Step 2: A relation is a function if each element in the domain is paired with one and only one element in the range.
Step 3: From the mapping diagram, it can be observed that the given relation is not a function as '3' in the domain is paired with two elements - 1 and - 2 in the range and '6' is paired with - 1 and - 2.