# Question #af1dd

##### 1 Answer

See below for details.

#### Explanation:

When relations are defined by a set of paired values,

the first value in each pair is a Domain element

and the second value is a Range element.

We typically say that, for each pair the Domain element "maps into" the Range element.

A relation is a function if no Domain value "maps into" more than one Range value.

For the relations:

the pairs

#(2,3)# and#(2,5)# map the same Domain value (#2# ) into different Domain values (#3# and#5# );

therefore#A# isnota function.

the pairs

#(1,2)# and#(1,3)# map the Domain value (#1# ) into different Range values;

#B# isnota function.

the pairs

#(1,2)# and#(1,5)# map the Domain value (#1# ) into different Range values;

#C# isnota function.

there are no Domain values which map into more than one Range value;

#D# isa function.

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The Range of the relation

is the set of Range values, namely