Which of the following would be a testable hypothesis for an experiment that compares the health of salmon raised in fish farms to salmon caught in the wild?

If Salmon are raised in a fish farm then they will be healthier since they aren't being exposed to predators or disease.

I'm not fully sure if this is good enough since it seemed like your question had multiple choice but this is generally a testable hypothesis.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current