Consider the reaction below:
A + C₂ → AC₂
The reaction is first-order in A and first-order in C₂.
Two mechanisms are proposed for the reaction: 
Mechanism 1 (single-step):
A + C₂ → AC₂  
Mechanism 2:
B + C₂ → BC + C slow
A + BC → AB + C fast
AB +  2 C → AC₂ + B fast
Are both mechanisms valid? If yes why? 

• A. Yes, because the overall reaction matches.
• B. Yes, because the rate law will be the same.
• C. No, because the rate law will not be the same.
• D. No, because B is added.

Answer: (C)