Sodium Iodide, NaI, Melts at 651 ^$\circ$ C in Its Liquid State NaI Conducts Electricity

Multiple Choice

Sodium iodide, NaI, melts at 651 ^$\circ$ C. In its liquid state NaI conducts electricity. What kind of crystal is this

A) Ionic Crystal
B) Covalent Crystal
C) Metallic Crystal
D) Molecular Crystal
E) Amorphous (Not a regular crystal)