In the diagram, section A represents:

A) N-type germanium
B) P-type germanium
C) Anode
D) Diode

Hint: From figure when external source is applied then the charges get aligned and the excess of electrons gathers at one place and holes at the opposite side. Excess of electrons is N and holes are of P type.

Complete solution:
Step 1:
Before starting the solution let us know about N and P type semiconductor.
An N-type semiconductor is a type of material used in electronics. It is made by adding an impurity to a pure semiconductor such as silicon or germanium. The impurities used may be phosphorus, arsenic, antimony, bismuth or some other chemical element. They are called donor impurities.
A P-type semiconductor is a type of semiconductor. When the trivalent impurity is added to an intrinsic or pure semiconductor (silicon or germanium), then it is said to be a p-type semiconductor. Trivalent impurities such as Boron, Gallium, Indium, Aluminum etc are called acceptor impurity.

Step 2:
In N-type material there are electrons energy levels near the top of the band gap so that they can be easily excited into the conduction band. In P-type material, extra holes in the band gap allow excitation of valence band electrons, leaving mobile holes in the valence band.
So from the figure we can see that A has more number of electrons and B part has the maximum number of holes so A represents N-type Germanium.

Hence, option A is correct.

Additional information: Anode: The anode is the electrode where electricity moves into. The cathode is the electrode where electricity is given out or flows out of. The anode is usually the positive side.
Cathode: A cathode is the metallic electrode through which current flows out in a polarized electrical device. Cathodes get their name from cations (positively charged ions) and anodes from anions (negatively charged ions). In a device that uses electricity, the cathode is the negatively charged electrode.

Note: Semiconductors are especially made up of germanium and silicon because they have free electrons in their outer shell and hence offer conductivity. Germanium at a given temperature offers more free electrons than silicon. That’s why they are widely used in transistors and other electronic devices.