Final answer:
The limit t of the sequence (tn), which contains elements from the set of subsequential limits S, belongs to S since S is closed with respect to limits of sequences.
Step-by-step explanation:
If we have a sequence (sn) and the set S represents the subsequential limits of (sn), and we have a sequence (tn) where each tn belongs to set S, and this sequence (tn) has a limit t, then t will belong to the set S. This is because the subsequential limits of a sequence form a closed set, meaning that if a sequence of points within this set has a limit, this limit point is also within the set. Hence, the correct answer is A. S.