Users of bitcoin often see their keys represented in hexadecimal format because Select one: a. there are 16 characters in a bitcoin private key b. there are 6 characters in a bitcoin private key c. it's more convenient for humans to read than binary format d. it's more convenient for humans to read than decimal format Every block in Bitcoin contains a NONCE parameter. Consider the Bitcoin block hash: 00000000000000000006f7 de74164366a7508200896eb33faaefd7994bda3e86, how would changing only the nonce paramer in this beader data by one bit affect the resulting block hash? a. The hash output would be 10000000000000000006f7de74164366a7508200896eb33faaefd7994bda3e86 b. The output would be close, but not identical to 00000000000000000006f7 de74164366a7508200896eb33faaefd7994bda3e86 c. It would almost certainly NOT start with four zeros (0000) d. It would produce the same hash output, since the merkle route, version number, timestamp, difficulty and previous block hash are the same If you know the output of a SHA256 hash, Select one: a. it is trivially easy to guess what the input was b. it is infeasible to guess what the input was c. it is fairly hard to guess what the input was d. it is 100% impossible to guess what the input was