Based on QuarkChain's whitepaper, which one is correct?*
A. Only powerful parties can run a super-full node.
B. Users need multiple accounts (with different private keys) in different shards.
C. It is reshardable after main-net launched.
D. Rootchain records transactions details.

I have A. Right?

And,
Suppose current QuarkChain network supports A cross-shard transactions per second, how many cross-shard transactions per second can be supported after doubling the number of shards?*
A. AA
B. A
C. 4A
D. 2*A

I don't know this anwser. could you anwser me?