Facts about Five Elements

\begin{tabular}{|l|c|c|c|c|}
\hline
\multicolumn{1}{|c|}{Element} & \begin{tabular}{c}
Atomic \\
mass (amu)
\end{tabular} & \begin{tabular}{c}
Total \\
electrons
\end{tabular} & \begin{tabular}{c}
Valence \\
electrons
\end{tabular} & Year isolated \\
\hline
Aluminum (Al) & 27 & 13 & 3 & 1825 \\
\hline
Boron (B) & 11 & 5 & 3 & 1808 \\
\hline
Carbon (C) & 12 & 6 & 4 & 1803 \\
\hline
Gallium (Ga) & 70 & 31 & 3 & 1875 \\
\hline
Germanium (Ge) & 73 & 32 & 4 & 1886 \\
\hline
\end{tabular}

Which of the following statements is most likely true?

A. Boron and carbon are likely together in one period because they have very close atomic masses, while gallium and germanium are likely together in another period because they have very close atomic masses.

B. Aluminum, boron, and carbon are likely together in one period because they were first isolated in the first half of the 1800s, while gallium and germanium are likely together in another period because they were first isolated in the second half.

C. Boron and carbon are likely together in one period because they each end in "-on," while aluminum, gallium, and germanium are likely together in another period because they each end in "-ium."

D. Aluminum, boron, and gallium are likely together in one group because they have the same number of valence electrons, and carbon and germanium are likely together in another group because they have the same number of valence electrons.