Which of the following statements are correct?
A. The process of generation of conduction electrons and holes and process of recombination is a simultaneous process.
B. To increase the conductivity of a semiconductor manifold, a few parts per million of a suitable impurity is added.
C. Extrinsic semiconductors doped with trivalent impurity are called n-type semi conductors.
D. During the formation of a p-n junction, two processes diffusion and drift occurs.
E. The thickness of depletion region is of the order of a millimeter.
Choose the correct answer from the options given below:

1. A C, D and E Only
2. B A, B and D Only
3. C A, D and E Only
4. D B, C and E Only