The Space Between the Inner Wire of Radius a = $\kappa$

Multiple Choice

The space between the inner wire of radius a = 1 mm of a co-axial cable and the conducting shield of radius b = 8 mm is made of nylon ( $\kappa$ = 4.2) .A potential difference of 20 V is maintained between the wire and the shield.The energy stored per meter of the cable is

A) 1.12 nJ/m
B) 22.5 nJ/m
C) 44.9 nJ/m
D) 5.36 nJ/m
E) 2.68 nJ/m