Which of the following represents the correct decreasing order of the ionic character of metal halides?

Fluorine is the most electronegative element in the periodic table. Thus, when it reacts with a metal $\mathrm{M}$, its electronegativity difference is ought to be the most. 

So, it will be the one with the most ionic character. Thus, the ionic character of metal halides decreases as we go down the group as the electronegativity difference also decreases and the covalent character increases.

Hence, the correct answer is option A) MF $>\mathrm{MCl}>\mathrm{MBr}>\mathrm{MI}$