Select the correct statements regarding the mechanism of muscle contraction.
$A.$ It is initiated by a signal sent by $\text{CNS}$ via a motor neuron.
$B.$ Neurotransmitter generates an action potential in the sarcolemma.
$C.$ Increased $Ca^{++}$ level leads to the binding of calcium with troponin on actin filaments.
$D.$ Masking of the active site of actin prevents contraction; unmasking leads to contraction.
$E.$ Utilising the energy from $\text{ATP}$ hydrolysis to form a cross-bridge.

• A
  $A, B, C, D$ and $E$
• B
  $A, B, C$ and $E$ only
• C
  $B, C, D$ and $E$ only
• D
  $A, B, C, D$ and $E$ are all correct