A 4 : 1 molar mixture of `He` and `CH_(4)` is contained in vessel at 20 per pressure. Due to a hole in the vessel the gas mixture leakes out. What is the compostion of mixture effusing out initially.
A. `33.3% He, 66.7% CH_(4)`
B. `66.7% He, 33.3% CH_(4)`
C. `40% He, 60% CH_(4)`
D. `60% He, 40% CH_(4)`