A mass spectrum for a lithium sample indicates the presence of two isotopes, $^6\text{Li}$ and $^7\text{Li}$. The isotopic abundances are given in the table: $^6\text{Li}$ = $7.42\%$, $^7\text{Li}$ = $92.58\%$. What is the relative atomic mass of this lithium sample, to three significant figures?
- A$6.07$
- B$6.50$
- C$6.90$
- D$6.93$