A radioactive sample has activity A₀ at t=0. What will be the activity of the sample after two half-lives?

A. zero
B. \(\frac{{{A_0}}}{4}\)
C. less than \(\frac{{{A_0}}}{4}\) if the sample is kept at high pressure
D. greater than \(\frac{{{A_0}}}{4}\) if the sample is kept at high temperature

B