Answer
d) is the correct answer.
Work Step by Step
1. Count the molecules on the initial vessel.
6 CO and 3 $O_2$.
2. If, according to the balanced equation, 2 CO and 1 $O_2$ produces 2 $CO_2$. 6 CO and 3 $O_2$ (3 times that), can produce 6 $CO_2$.
3. Identify the vessel with 6 $CO_2$:
- It is d)
