Determine the Intervals of the Domain for Which the Function $[ 1 , \infty )$

Multiple Choice

Determine the intervals of the domain for which the function is increasing, decreasing, and constant.
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A) Increasing $[ 1 , \infty )$ ; Decreasing $( - \infty , 1 ]$
B) Increasing $( - \infty , 1 ]$ ; Decreasing $[ 1 , \infty )$
C) Increasing $[ 1 , \infty )$ ; Decreasing $[ 1 \infty )$
D) Increasing $( - \infty , 1 ]$ ; Decreasing $( - \infty , 1 ]$