Among the following solids the number of  ionic solid(a) Tetra phosphorus deca-oxide (P4O10)(b) Graphite              (c) Brass(d) Ammonium phosphate (NH4)3PO4(e) SiC                      (f) Rb(g) I2                       (h) LiBr(i) P4                       (j) Si(k) Plastic