Final answer:
Out of the options provided, 5 sets of 5 reps has the potential to increase muscular strength the most because it balances a moderate number of repetitions with a higher overall volume and typically involves lifting heavier weights which are beneficial for strength gains.
Step-by-step explanation:
The potential to increase muscular strength is most influenced by the volume and intensity of the exercise performed. Among the options provided, 5 sets of 5 reps has the highest potential to increase muscular strength. This is because performing multiple sets with a moderate number of repetitions allows for a higher overall volume while still maintaining a load that is heavy enough to require the muscles to adapt and grow stronger. Higher rep ranges, such as 15 reps, are typically associated with muscular endurance rather than strength.
Training programs for strength typically involve lifting heavy weights for a lower number of reps, to focus on the neuromuscular adaptations required for strength gains. On the other hand, a single set, whether it is of 5 reps or 15 reps, is not likely to be sufficient volume to stimulate maximal strength gains as compared to multiple sets. Therefore, the best choice for maximum strength gain is to engage in a program with a higher volume of sets, specifically option a, which is 5 sets of 5 reps.