What is the reason for the sudden rise in the BTG price?
There's no news about BTG development.
https://coinmarketcap.com/currencies/bitcoin-gold/news/This is a pump and dump coin and i think that is a common thing to see that BTG already pumped so hard again. I think that it's not only BTG but bitcoin diamond as another fork of bitcoin will be pumped as well.
No reason for this pump and BTG has a very weak fundamental.