Consider the following mechanism and use it to answer the questions that follow.

Step $1$:

$A+Ax$

$[$slow$]$

Step $2$

$x+BC+Y$

Step $3$:

$Y+B-D$

$[$fast$]$

a$.$ Write the overall reaction.

b$.$ Identify any species that are reactants, products, intermediates, and$/$or transition states.

c$.$ Write the rate law for this reaction and explain your rationale.