Q. 33 was about changes in brain lead to mathematical abilities, This is what i can recall and It is certainly True going by the article published here -
https://www.theguardian.com/theguardian/2005/feb/12/weekend7.weekend2
For the Q. "Study already been carried out"..That ARC paragraph was definitely not the answer. So I marked as C where Professor Allan Snyder, from the Centre for the Mind at the Australian National University in Canberra, explains why Tammet is of particular, and international, scientific interest.