How many $C{l}^{–}$ ions are there around $N{a}^{+}$ ion in NaCl crystal?

According to electrostatic principles, each ion in solid sodium chloride is surrounded by six other ions that have the opposite charge. The vertices of a typical tetrahedron are where the surrounding ions are found. The larger chloride ions are placed in a cubic array in the manner of close packing, and the smaller sodium ions occupy all of the cubic gaps (tetrahedral voids) in between.
Hence, the correct option is option (C) 6.