This axiom follows from LPO, because we have a choice sequence if either A(n) is inhabited for all n, or empty for some n.
It also follows from the axiom of weak countable choice (WCC) from Bridges, Richman and Schuster,
A Weak Countable Choice Principle. This is because, given C(n) as in (**), we can inductively define a new sequence of sets D(n) with at most one non singleton as below:
Take D(n) to be A(n) if A(m) is inhabited for all m <= n
Take D(n) to be B if A(n) is empty, but A(m) is inhabited for all m < n
Take D(n) to be {0} if A(m) is empty for some m < n
Then D(n) has at most one non-singleton, so we can apply WCC to get a choice sequence d(n) \in D(n).
Now apply induction again to get a choice sequence c(n) for C(n):
If A(n) is inhabited, take c(n) to be the unique element of A(n).
If A(n) is empty, take c(n) to be d(m) where m <= n is least such that A(m) is empty
However, I think this axiom fails in the topological model over the product of Cantor space with the unit interval, 2^N x [0,1]. Define A(n) to be a subset of {0} and B to be a subset of {0,1} as follows. Given a point (a, x) of the topological space, take A(n) to be equal to {0} if a(n) = 1 and empty otherwise. Take B to contain 0 iff for some n a(n) = 0 and x < 1/2 + 2^{-n}. Take B to contain 1 iff for some n a(n) = 0 and x > 1/2 - 2^{-n}. (And so if a(n) = 0 for some n and 1/2 - 2^{-n} < x < 1/2 + 2^{-n} then B = {0, 1}). Then I don't think there can be any choice sequence defined on any neighbourhood of the point (1, 1/2).
Best,
Andrew