Answer:
Option (2)
Explanation:
Formula to determine the final amount of an element after t years is,
![A_t=A_0e^(kt)](https://img.qammunity.org/2021/formulas/mathematics/high-school/2kagroo6jna3qxvaal2s0f1kr7aipxl06u.png)
where
= Final amount
= Initial amount
t = Duration or time
k = decay constant
If the half life period of a C-14 isotope = 5730 years
[For half life period]
![(A_0)/(2)=A_0e^((5730)k)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ur9vpnn391twmcpfduit5snvmagxkh56h6.png)
![e^(5730k)=0.5](https://img.qammunity.org/2021/formulas/mathematics/high-school/idh3jxb21ryshkpqqttz5lpcj9eqxs3qta.png)
![\text{ln}(e^(5730k))=\text{ln}(0.5)](https://img.qammunity.org/2021/formulas/mathematics/high-school/b0xouvot2w2qfa840lvzpn8vxwqgmdzaeq.png)
0.5730k = -0.6931
k =
= -0.000121
Therefore, formula for the radioactive decay will be.
![A_t=A_0e^(-0.000121t)](https://img.qammunity.org/2021/formulas/mathematics/high-school/7icbcq7mg73ukl9rpj0m69wtog9rmpwejk.png)
Option (2) will be the answer.