Let's find the electron configuration of each atom
Atom atomic number electron configuration
Bo 5 1s2 2s2 2p
F 9 1s2 2s2 2p5
Na 11 1s2 s2 2p6 3s
K 19 1s2 2s2 2p6 3s2 3p6 4s
The spherically shaped orbitals are the s orbitals.
You can se in the table that I wrote above that sodium has 2 electrons at 1s, 2 electrons at 2s and 1 electron at 3s orbitals, that is a total of five electrons at s (spherically shaped orbtials).
So the answer is the option A) sodium.
