a)ATP get hydrolyzed, because of their elements in normal saline solution of suspension.
I think with questions like this it’s easier to simplify the question after you’ve read all the answers. The underlying question is “what cause ATP hydrolysis during muscle contraction”. The answer to that question is “ATP hydrolysis occurs at the myosin ATPase” I would agree that A is the correct answer because myosin ATPase induces hydrolysis of ATP allowing interaction with actin. B is incorrect as actin does not hydrolyse ATP. C is wrong as calcium results in the conformational change of troponin which exposes the actin filament so that actin and myosin can interact but does not play a role in ATP hydrolysis. D is wrong for the same reason as answer C. Anyone feel free to correct me if my reasoning is incorrect! I think it is safe to say that only a small amount of ATP would be hydrolysed initially without repetitive cross bridge cycling. I would read up further on the muscle contraction as I am just a student and no expert!