What two sequential events each require a Ca$2+-$binding protein?

Question $85$ options:

$1)$ kinesin microtubule trafficking, $2)$ myosin actin trafficking

$1)$ synaptic vesicle fusion, $2)$ action potential propagation

$1)$ neurotransmission, $2)$ excitation$-$contraction coupling

$1)$ action potential propagation, $2)$ synaptic vesicle fusion

$1)$ striated muscle contraction, $2)$ action potential propagation