Which of the following statement is correct

Options

A. helium 5 and helium 3 are radioactive nuclides with short half lives
B. `H_(2)^(4)` is obtained from the decay of `H_(1)^(3)`
C. Helium is the most aboundant noble gas in the atmosphere
D. helium 4 has a low molecular viscosity and a large mean free path

Answer

A

Explanation

Half life periods of radio active elements are only measurable