Group 13 metals have three valence electrons

Steps:

• Locate elements in group 13 of the periodic table, which have three outer shell electrons.
• Identify metals within this group; boron is a metalloid, while aluminum and below are metals.
• Examine the diagram's section to match choices to these elements.
• Select the option corresponding to a group 13 metal.

Why B is correct:

• Option B represents aluminum, a group 13 metal with exactly three valence electrons per the periodic table's group numbering system.

Why the others are wrong:

• A is boron, a metalloid, not a metal.
• C is likely a group 14 element like carbon, with four valence electrons.
• D is probably a transition metal or group 2 element, lacking exactly three valence electrons.

Final answer: B