The correct answer to the Half Twisting Roll quiz is first Legal in Level 3. In Level 2 log rolls must start and end in cradle position, which the skill in the video does not. In Level 3, generally release moves may not twist, but there is an exception stating:
Log/barrel rolls may twist up to one rotation and must land in a cradle, or flat and horizontal, body position
The skill in the video meets this exception, making it Legal in Level 3.
This ruling and explanation are based on the 2016-17 version of the rules dated August 31, 2016.