Why does the compound sodium fluoride contain an ionic bond?

A.
The fluorine transfers one electron to the sodium to fulfill the octet rule.

B.
The sodium transfers one electron to the fluorine to fulfill the octet rule.

C.
The fluorine must share an electron with the sodium in order to fulfill the octet rule.

D.
The sodium must share an electron with the fluorine in order to fulfill the octet rule.

A. The fluorine transfers one electron to the sodium to fulfill the octet rule.