In this type of question, we will use the exponential equation
![y=a(b)^x](https://img.qammunity.org/2023/formulas/mathematics/college/x4kto8751eypenmr0i3prbmrtznyb1ero8.png)
Where:
a is the initial amount
b is the factor of growth or decay
Since it is a half-life, then
b = 1/2 = 0.5
Since it is now 50 grams, then
a = 50
Since x is the number of years, then
x = 700
Substitute them in the rule above
![\begin{gathered} y=50(0.5)^(700) \\ y=0 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/72vzlfzzteupgebkczok98tidxy1pvbec3.png)
It will be representing 0 grams after 700 years
The answer is A