Application of a forward bias to a $P-N$ junction

In the following figure,the diodes which are forward biased,are

Which of the following circuits is reverse-biased?

$A$ silicon diode has a forward voltage drop of $1.2\, V$ for a forward $DC$ current of $100\, mA$. It has a reverse current of $1\times10^{-6}\, A$ for a reverse voltage of $10\, V$. The bulk and reverse resistances of the diode are:

Explain the forward and reverse characteristics of the $p-n$ junction diode by drawing the circuit and graph.

Refer to the circuit diagram given in the figure. Which of the following observations are correct?
$A.$ Total resistance of the circuit is $6 \ \Omega$.
$B.$ Current in the ammeter is $1 \ A$.
$C.$ Potential across $AB$ is $4 \ V$.
$D.$ Potential across $CD$ is $4 \ V$.
$E.$ Total resistance of the circuit is $8 \ \Omega$.
Choose the correct answer from the options given below: