Answer:
Option, A and C
Explanation:
The two steps reaction is as follows:
A(g) + B(g) → X(g) + Y(g) first step
X(g) + C(g) → Y(g) + Z(g) second step
In both the mechanism, two molecules are involved as the reactants, therefore, it both the steps are bimolecular.
Substance 'X' formed in first step and consumed in the second step. So, it a an intermediate species.
For overall reaction, add both the steps:
A(g) + B(g) + C(g) → 2Y(g) + Z(g)
Therefore, the correct options are option A and C