Sum of the first

*n* terms

$S_n = 3^{2n - 1} + b$

*n*^{th} term

$a_n = S_n - S_{n - 1}$

$a_9 = S_9 - S_8$

$a_9 = (3^{17} + b) - (3^{15} + b)$

$a_9 = 114,791,256$

$a_7 = S_7 - S_6$

$a_7 = (3^{13} + b) - (3^{11} + b)$

$a_7 = 1,417,176$

$\text{Quotient} = \dfrac{a_9}{a_7} = \dfrac{114,791,256}{1,417,176}$

$\text{Quotient} = 81$ ← Answer: [ A ]