For diode $D_1$,the forward bias resistance is $20 \ \Omega$ and the reverse bias resistance is $600 \ \Omega$. For diode $D_2$,the forward bias resistance is $30 \ \Omega$ and the reverse bias resistance is $200 \ \Omega$. Find the equivalent resistance between $A$ and $B$ if $(i)$ $A$ is at a higher potential,and $(ii)$ $B$ is at a higher potential.

• A
  $\frac{200}{7} \ \Omega$ and $\frac{200}{11} \ \Omega$
• B
  $\frac{200}{11} \ \Omega$ and $\frac{200}{7} \ \Omega$
• C
  $50 \ \Omega$ and $800 \ \Omega$
• D
  $220 \ \Omega$ and $630 \ \Omega$