Discuss the Rate of Limit in Overall Reactions

Question

The overall reaction
 
   A → B
 
proceeds via the following elementary steps

1) A + S ⇄ AS      r₁ = k₁ [ C_AC_S– C_AS/K_A ]
2) AS ⇄ BS           r₂= k₂ [C_AS – C_BS/K_S ]
3) BS ⇄ B + S      r₃= k₃ [C_BS– C_BC_SK_B ]

If C_S = C_Stot/(1+k_xC_A + k_xk_yC_A)
 
where k_x and k_y could either be k_A, k_S, or k_B

Which step is rate limiting?

a) Step 1
b) Step 2
c) Step 3
d) Not enough info

Summary

The question belongs to Chemical Engineering and the question is about rate of limiting in overall reactions.