The correctly drawn lewis structure for boron is B! To draw the lewis dot structure, you need to find the number of valance electrons (boron has 3) and then put a dot for each valance electron around the symbol for the atom. However, instead of putting three in different rings you're going to smush two together, so it has some sort of stability shown.
To determine this answer, we can use the number of valence electrons that boron has. Since it is in group 3 of the periodic table, the Lewis dot diagram will need to have 3 dots around it, representing the 3 valence electrons. Therefore, the only diagram with 3 dots is the second one, making it the correct choice.
