I need the explaination and the answer. thank u

Step-by-step explanation:

The americium is represented as 1. Every 432 years it decreases by 50%.

First half-life:

432 years.

0.50 (1/2) of americium remains after 432 years.

Second half-life:

0.25 (1/4) of the americium remains.

Third half-life:

0.125 (1/8) of the americium remains.

Last half-life:

0.0625 (1/16) of the americium remains.

Option B is correct.