$A$ rectangular carbon block has dimensions $1.0 \ cm \times 1.0 \ cm \times 50 \ cm$. The resistance is to be measured first between the two square ends and then between the two rectangular ends. If the resistivity of carbon is $3.5 \times 10^{-5} \ \Omega \cdot m$,find the values of the resistances in both cases respectively.

• A
  $17.5 \times 10^{-2} \ \Omega, 7 \times 10^{-6} \ \Omega$
• B
  $7.5 \times 10^{-5} \ \Omega, 7.5 \times 10^{-2} \ \Omega$
• C
  $17.5 \times 10^{-4} \ \Omega, 7 \times 10^{-7} \ \Omega$
• D
  $7.5 \ \Omega, 7 \times 10^{-2} \ \Omega$