Answer:
Gas B
Explanation:
diffusion/effusion increases when:
- Temperature increases
- A gas has lower molar mass
- Particles are moving quickly
diffusion/effusion decreases when:
- Temperature decreases
- A gas has higher molar mass
- Particles are moving slowly
Hence: since gas B has the lowest molar mass, it has the highest rate of effusion
I also took the test so I know it is right