A Radioactive Sample Has an Activity R

Multiple Choice

A radioactive sample has an activity R.For which of the following changes would the activity remain unchanged?​

A) ​The number of radioactive nuclei in the sample is doubled.
B) ​The half-life of the radioactive nuclei is doubled.
C) ​The decay constant is doubled.
D) ​A time period equal to two half-lives is allowed to elapse.
E) ​All of the above changes result in a change in the activity.