Which of the following are most likely to form a stable ionic bond

a. Carbon (Period IVA) and Oxygen (Period VIA)
b. Lithium (Period IA) and Fluorine (Period VIIA)
c. Magnesium (Period IIA) and Iron (Period VIIIB)
d. Potassium (Period IA) and Tin (Period IVA)

b. Lithium (Period IA) and Fluorine (Period VIIA)