The right answers are:

c) Delegated proof of stake
c) steem and bitshares
a) 15 out of 21

The amiunt of SBD awarded for this post is 0.24 SBD.
There is no BEST answer.
The first correct answer was the one made by the user @moriartyroue. So the reward is 15% since there is no BEST answer + 10% for the first correct answer = 0.036 + 0.024 = 0.06
There was no upvote on the first correct answer therefore the other 25% will not be paid.
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