The resistance of a strip of copper of rectangular cross section is 2 Ω. A metal of resistivity twice that of a copper is coated on its upper surface to a thickness equal to that of copper strip. The resistance of composite strip will be

• A.  6 Ω.
• B.  3 / 2 Ω.
• C.  3 / 4 Ω.
• D.  4 / 3 Ω.

Answer: (D)