Answer:
C. MgCl2
Step-by-step explanation:
Binary compound are chemical compounds composed of 2 different elements. Elements are substance that can not be separated. The elements that makes up a binary compound are not the same. A good example of a binary compound is NaCl . The sodium chloride compound has one atom of sodium and one atom of chlorine. Sodium and chlorine combined together to form a binary compound known as sodium chloride.
Among the options, MgCl2 pronounce as Magnesium chloride contains two distinct elements . But the number of atom of Magnesium is one while the number of atom of chlorine is 2. Both distinct elements combine together to form a binary compound.
All other option has more than two elements that makes up the compound.