Final answer:
A moderate dose of caffeine, approximately 200 mg to 400 mg, is recommended for endurance athletes to enhance performance. The effectiveness depends on the athlete's body weight, and even 100 mg can be beneficial for 'caffeine-naive' individuals or those with low physical fitness. Dose C (200 mg) is often recommended, but individual responses can vary.
Step-by-step explanation:
For endurance athletes looking to enhance performance through the use of caffeine, a moderate dose is typically recommended. Considering the research showing that a dose around 5 mg/kg body weight can improve various aspects of athletic performance, the amount of caffeine deemed most effective can vary depending on the athlete's weight. For an average adult, this might translate to approximately 200 mg to 400 mg of caffeine before exercise. This range is effective for improving endurance capacities, like sprint performance, cycling and running time trial performance, as well as other endurance-related measures.
Specifically, the consumption of caffeine before aerobic exercise has been associated with increased fat oxidation and a reduced perception of exertion, which can greatly benefit endurance athletes. However, there may be individual variability in response to caffeine, and it's important to consider factors such as the individual's caffeine tolerance and whether they are 'caffeine-naive'.
Therefore, based on the suggested dosage and the research, options B (100 mg) and C (200 mg) may both be considered within the effective range for an average individual, yet C (200 mg) might be more optimal for a regular caffeine consumer. For those new to caffeine consumption or with low physical fitness, even smaller doses (potentially option B) could be effective to improve endurance performance.