A nichrome wire 50 cm long and 1 mm cross-section carries a current of 4 A when connected to a 2 V battery. The resistivity of nichrome wire is

A. 1×10⁻⁶Ω−m
B. 2×10⁻⁷Ω−m
C. 3×10⁻⁷Ω−m
D. 4×10⁻⁷Ω−m