A student moves one end of a stretched rope up and down while, at the same moment, another student blows a whistle. Which option correctly classifies the two disturbances?
a) Rope: longitudinal, mechanical; Whistle: transverse, mechanical
b) Rope: transverse, non-mechanical; Whistle: longitudinal, non-mechanical
c) Rope: transverse, mechanical; Whistle: longitudinal, mechanical
d) Rope: transverse, mechanical; Whistle: transverse, mechanical