Final answer:
Medicare compensates co-surgeons by paying 125% of the global fee, which is then split equally, giving each surgeon 62.5% of the fee.
Step-by-step explanation:
When two surgeons of different specialties perform a procedure as co-surgeons, Medicare pays 125% of the global fee, dividing the payment equally between the surgeons.
Therefore, the correct answer is D. 125. This is to account for the additional costs and complexity that may arise when multiple specialists are involved in a surgical procedure. Each surgeon receives an amount equivalent to 62.5% of the total fee, summing to a combined payment that is 25% more than the standard fee for a single surgeon.