The correct sequence of increasing covalent character is represented by :

The covalent character of a compound increases as the electronegativity difference between the atoms decreases. In the given options, we compare the electronegativity differences for LiCl, NaCl, and BeCl2. LiCl and NaCl are both ionic compounds formed from alkali metals (which have low electronegativities) and chlorine (which has a high electronegativity). BeCl2, being a compound of a smaller, more highly charged cation (Be2+), exhibits more covalent character than the alkali metal chlorides due to the higher polarization of the anion by the small, highly charged Be2+ ion. Among LiCl and NaCl, LiCl has a slightly higher covalent character than NaCl because lithium has a higher electronegativity than sodium, resulting in a smaller electronegativity difference with chlorine. Therefore, the correct sequence of increasing covalent character is NaCl < LiCl < BeCl2.