Help me pick the next topic — what should I explain next?

$BTC $ETH
1. Bitcoin basics — how Bitcoin actually works
2. Ethereum — what makes it different from Bitcoin
3. How charts work — reading a price chart simply
4. Crypto safety — how to avoid scams and stay safe
Vote in the poll below, or just comment 1, 2, 3 or 4.
I will explain the winning topic in my next post, in simple words.
Not financial advice. DYOR.