Answer:
Third option is the correct choice.
Step-by-step explanation:
[tex]a_1[/tex] is the first term of the sequence which is given to be 1.
[tex]r[/tex] is the common ration which can be found as:
[tex]r=\frac{3}{1}=3\quad r=\frac{9}{3}=3[/tex]
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