Final answer:
Muscle tissues receive the most cardiac output at 60%, the VRG receives 20%, and fat tissues receive 15%. The correct match from the options is 'a) 2, b) 3, c) 1'.
Step-by-step explanation:
To assign the correct percentage of cardiac output (CO) that each tissue group receives, we should be aware of the typical blood flow distribution in the human body at rest. In general, muscle tissues receive the bulk of the cardiac output due to their high metabolic demand, especially during physical activity. Therefore, we can infer that muscle tissue receives the largest percentage, which is 60%. Visceral organs, such as those in the visceral region (VRG), receive a significant but lesser amount of blood flow, estimated at 20%. Lastly, adipose tissue (Fat) has a relatively low metabolic demand and blood flow requirement, so it would receive the smallest share of the cardiac output, which is 15%.
Based on this reasoning, our final answer would be: a) VRG - 20%, b) Fat - 15%, c) Muscle - 60%. This corresponds to the option 'a) 2, b) 3, c) 1' from the multiple-choice options provided by the student.