add 23 on both sides
as we can see it's a geometric progression.
q = a2/a1
q = 1/3
an = a1 . q^(n - 1)
an = 3 . (1/3)^(n - 1)
the one which matches is f(n) = 3 . (1/3)^(n - 1)
here the given expression,
we can write,
therefore, option b is correct.
the sum of 11 and m is greater than -23.