The correct answer to the Arabesque to Cradle Position quiz is the skill is Illegal in Level 2. As performed in the video, the back under one foot of the top person while the top is above his head. This makes the skill an extended single let stunt, which is not allowed in Level 2 (Stunts B1).
The video below, with the back on both ankles of the top person instead of being under the top person’s foot, is a version that is Legal in Level 2.
This ruling and explanation are based on the 2016-17 version of the rules dated August 31, 2016.