In a course I'm taking the following question came up:
A 51% attack means:
A. 51% of the nodes are bots
B. 51% of the nodes are hackers
C. 51% of the nodes are offline or disabled
D. 51% of the nodes agree on something
I had answered D, but the correct answer was given as B.
As far as I am aware, I believe that it was required (in a proof of stake system) to acquire 51% of the staked coins. From my understanding, a group of billionaires could get together to acquire said value, and as such, I answered D - 51% of the nodes agree on something, which while is not the way I would choose to answer it if I had the choice, I thought was more accurate than the hacker answer.
I'd think the right information should be: "A 51% attack is when one entity (which may comprise sub-entities) controls 51% of the network's consensus mechanism (be it mining power or value staked), enabling them to manipulate the blockchain." This answer does not contain the term "nodes" nor does it contain the term "hackers".
I tried to talk to the course-coordinator about this and he told me to do more research. The only way for me to do that, due to the specificity of the question, is to ask the opinions of learned people. If there is a better forum for me to post this on, please point me toward it.