Final answer:
Training at a high intensity range of 70-80% of 1RM is most conducive to acute increases in testosterone levels during and immediately after a resistance training session. Hence, option (C) is correct.
Step-by-step explanation:
The student asked which intensity range would be most conducive to acute increases in testosterone levels during and immediately after a resistance training session. The best option among those provided for this goal would be C. High intensity (70-80% of 1RM). Training at a high intensity is acknowledged for causing significant acute hormonal responses, including an increase in testosterone, which is beneficial for muscle growth and overall strength development.
Options A and B, low and moderate intensity, are less likely to elicit such a hormonal response, and while option D, very high intensity, might similarly increase testosterone levels, it is typically not sustainable for regular training due to the high risk of injury and overtraining.