For a series ∑n=1∞an, the limit n→∞liman is evaluated. Which of the following conclusions is always valid?
a) If n→∞liman=0, the series must converge.
b) If the limit is non-zero or does not exist, the series diverges.
c) If n→∞liman=∞, the series may converge.
d) If the limit does not exist, no conclusion can be drawn about convergence.