Final answer:
The series converges to s when the sequence of partial sums converges to s. The correct answer is A. Sequence of partial sums.
Step-by-step explanation:
The series converges to s if the sequence of partial sums converges to s. Therefore, the correct answer to the given question is A. Sequence of partial sums. In the context of series and summation, convergence of a series is defined as the limit of the sequence of its partial sums. If the sequence of partial sums approaches a finite limit as n approaches infinity, then the series is said to be convergent.