Questions with a Bitcoin (B) sign are questions about crypto assets. These can be questions about ICOs, cryptocurrency prices, crypto-related events, etc.
There is a BTC prize for correctly answering questions about crypto assets. For each correct answer you will receive a certain number of points. At the end of each month, the prize fund is distributed between all analysts who have accumulated at least 1 point over the course of the month. You can read more about the rewards system here.
Please note that neither challenges nor contests (prize funds) in the Cindicator app have any relation to Apple Inc. or Alphabet Inc.