3. If an adversary fakes a block in a blockchain that uses hash pointers, where does the tampering show? Choose the correct answer! (1 point) (a) in the previous hash pointer value that doesn't match anymore (b) in all previous hash pointers (c) in all following hash pointers (d) in only the next following hash pointer (e) in Scrooge's signature 4. What are the problems with Goofy's coin and Scrooge's coin? Select the two right answers! (1 point) (a) In Goofy's coin, Alice can sell her coins twice. (b) In Scrooge's coin, Alice can sell her coins three times. (c) In Goofy's coin, Goofy can fake the whole blockchain. (d) In Scrooge's coin, Scrooge can fake the whole blockchaim. (e) Scrooge's coin is decentralized