The answers are diagrams, which represent various Lewis Structures. The Lewis structure is used to represent the bond that atoms have. The letters in the diagram represent that atoms and the elements. The element in question is O2, which is Oxygen.
There are two letter O's because two atoms of Oxygen make up the element O2. The dashes in the structure represent the bond that the two oxygens have with one another. The dots in the Lewis Structures can represent both a bond or represent when an atom is alone. When there is a double bond, there will be a double line.
The correct answer is option B
The Lewis structure for oxygen (O2) shows the bond between two oxygen atoms. Each has a total of 6 valence atoms making a sum total of 12. The two oxygen atom can both achieve a stable structure by sharing two pairs of electrons. The double bond they share is denoted by the double lines joining the two atoms.
Option A is wrong because a single bond wouldn’t help achieve a stable octet structure so they need to form another bond.
Option C is wrong because it is similar to option A in terms of number of bonds formed.
Option D is wrong because only 2 bonds are necessary to achieve a stable structure.