Which experiment proves that ammonia gas diffuses faster than hydrogen chloride gas?

• aExperiment 1 ($\ce{KMnO4}$)
• bExperiment 2 (liquid blue)
• cExperiment 3 ($\ce{HCl}$ and $\ce{NH4OH}$)
• dExperiment 7 ($\ce{AlCl3}$)