To be a little nit picky, when creating a question that you need to select 4 of 5 checkboxes, it's probably more appropriate to reword the question and have the audience select the one RADIO button that does not meet the needs.
For example, the question currently is written as: "Select 4 of these answers, which can potentially to reduce the frequency of hash bailouts." It should have been written as "Select which statement does not reduce the frequency of hash bailouts."
Also, having an "All of the above" option when it clearly says to select 4 is not necessary. If someone felt that "All of the above" was the correct answer, what other three should they select?