Answer:
C
Step-by-step explanation:
The explicit formula for a geometric sequence is
[tex]a_{n}[/tex] = a[tex](r)^{n-1}[/tex]
where a is the first term and r the common ratio
From the recursive formula
[tex]a_{n}[/tex] = - 9[tex]a_{n-1}[/tex]
The common ratio r = - 9 and with a = 300, then
[tex]a_{n}[/tex] = 300[tex](-9)^{n-1}[/tex] → C
