Given that gallium has two naturally occurring isotopes, $\ce{Ga-69}$ and $\ce{Ga-71}$, with an average atomic mass of $\pu{69.72 u}$, we can infer the relative abundances of these isotopes.

Since the average atomic mass ($\pu{69.72 u}$) is closer to the atomic mass of $\ce{Ga-69}$ (around $\pu{68.93 u}$) than to $\ce{Ga-71}$ (around $\pu{70.92 u}$), it indicates that $\ce{Ga-69}$ is more abundant than $\ce{Ga-71}$.

Therefore, the correct pie chart should show that $\ce{Ga-69}$ has a larger portion compared to $\ce{Ga-71}$. The answer corresponds to:

Choice C - The pie chart where the segment representing $\ce{Ga-69}$ is larger than that of $\ce{Ga-71}$.

Would you like further details or have any other questions?

Here are 5 related questions you might find interesting:

1. How do isotopic abundances affect the calculation of average atomic mass?
2. Why is the average atomic mass of gallium closer to $\ce{Ga-69}$ than $\ce{Ga-71}$?
3. What are the exact isotopic masses of $\ce{Ga-69}$ and $\ce{Ga-71}$?
4. How can you experimentally determine the relative abundances of isotopes?
5. What is the significance of isotopic abundance in chemistry and material science?

Tip: When analyzing average atomic mass, the closer the average is to an isotope's mass, the more abundant that isotope is.