The correct answer is option C
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Explanation of the answer:
It is given that ⇒ a₁ = -6
So, we need to find which of the options will give us -6 by substituting with n=1
⇒ substitute with n = 1 in the equation of option A
∴

⇒ substitute with n = 1 in the equation of option B

⇒ substitute with n = 1 in the equation of option C
∴

⇒ substitute with n = 1 in the equation of option D
