Some atoms are exceptions to the octet rule by having an expanded octet. which characterstic is needed for an atom to have an expanded octet

The characteristic that is needed for an atom to have an expanded octet is for the atom to have an empty d-orbitals.
According to the octet the sum of all the shared and unshared valence electrons about an atom must total 8 to have a stable species, which translates to 4 covalent bonds. However, some elements violate the octet rule and have what we call the expanded octet (the atom ends up with more than an octet); examples of such elements are sulfur, silicon, phosphorus and chlorine. 

If it isn’t a then it has to be d idk tho cause there’s no picture