As Aprt of in Vetro Experiment, the Physiologist Injet Radiolabeled

As aprt of in vetro experiment, the physiologist injet radiolabeled ATP into skeletal muscle. If the labeled ATP is observed to attach to the sacromere during muscle contraction. What does this attachement casue immediately?

A) Calcium binding to troponin C
B) Tropomyosin displacement from the groove on the actin molecule
C) Myosin head detachment from the actin filament
D) Cross-bridge formation
E) Myosin light chain phosphorylation by a specific enzyme