Samples of two radioactive nuclides A and B are taken. λ_{A} and λ_{B} are the disintegration constants of A and B respectively. In which of the following cases, the two samples can simultaneously have the same decay rate at any time?

(a) Initial rate of decay of A is twice the initial rate of decay of B and λ_{A} = λ_{B}.

(b) Initial rate of decay of A is twice the initial rate of decay of B and λ_{A} > λ_{B}.

(c) Initial rate of decay of B is twice the initial rate of decay of A and λ_{A} > λ_{B}.

(d) Initial rate of decay of B is same as the rate of decay of A at t = 2h and λ_{B} < λ_{A}.