The goal is not only to model the vector with 2 - D and to determine its important parameters, but also to examine the impact in the implementation. That is, Ogden's material parameters, element type, element size, and loading type.
C.supplementary is the right one
Prob(spinning a number < 3on 1 spin) = Prob( spinning 1 or 2) = 2/5
Prob( spinning <3 3 times) = 2/5 * 2/5 * 2/5 = 8/125
These events are independent so we multiply the probabilities.