Final answer:
The supplement of a 56-degree angle is found by subtracting 56 degrees from 180 degrees, resulting in 124 degrees. Therefore, the supplementary angle is 124 degrees.
Step-by-step explanation:
The supplement of a given angle is the angle which, when added to the given angle, results in a sum of 180 degrees since supplementary angles always add up to 180 degrees. Therefore, to find the supplement of a 56-degree angle, you subtract 56 degrees from 180 degrees.
180 degrees - 56 degrees = 124 degrees
Hence, the correct answer is C) 124 degrees.