The right answer is:

a) Delegated proof of stake
b) 3 seconds
c) Bandwidth is Information carrying capacity. It is used in order to avoid spam.

The reward of this post was 0.56 SBD.

The BEST answer is the one of the user @xex. The reward for the BEST answer is 15% so it is 0.084

The first user that has answered correctly was @xex. The reward is 10% so it is 0.056

The other 25% = 0.14 for upvotes on the best answer is not paid since there is no upvotes.

Thank you all for participating and for your contributions.