I would say B. Also C makes since too.
The answer is Protein. T<span>he primary type of macromolecule in the actin and myosin that make up muscle cells is Protein. </span>Muscles<span> are composed of two major protein filaments: a thick filament composed of the protein </span>myosin<span> and a thin filament composed of the protein </span>actin<span>. </span>Muscle contraction<span> occurs when these filaments slide over one another in a series of repetitive events.</span>
An unwanted physical or mental effect caused by a drug
