Find the Domain and Range of the Relation $( - \infty , \infty )$

Multiple Choice

Find the domain and range of the relation. Also determine whether the relation is a function.
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A) domain: $( - \infty , \infty )$ ; range: $( - \infty , \infty )$ ; function
B) domain: $( - \infty , \infty )$ ; range: $( - \infty , \infty )$ ; not a function
C) domain: $( 0 , \infty )$ ; range: $( 0 , \infty )$ ; function
D) domain: $( - \infty , \infty )$ ; range: $( 0 , \infty )$ ; not a function