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Direction (1 - 5): Read the given passages and answer the questions that follow.

There are certain substances that are neither good conductors (metals) nor insulators (glass). A substance which has crystalline structure and contains very few electrons at room temperature is called semiconductor. At room temperature, it behaves like an insulator. Its resistivity lies between that of conductor and insulator. If suitable impurities are added to the semiconductor, controlled conductivity can be provided. Some examples of semiconductors are silicon, germanium etc.

Current conduction in a semiconductor occurs through the movement of free electrons and holes collectively known as charge carriers. Adding impurity atoms to a semiconducting material, known as 'doping', greatly increases the number of charge carriers within it. When a doped semiconductor contains mostly free holes it is called "p-type" and when it contains mostly free electrons it is known as "n-type".

(Reference: Md. F. Rahman (2014). A Review on Semiconductors Including Applications and Temperature Effects in Semiconductors. American Scientific Research Journal for Engineering, Technology, and Sciences, Vol 7, No. 1, pp 50-70)

Silicon doped with electron-rich impurity forms:

A) p-type semiconductor

B) n-type semiconductor

C) intrinsic semiconductor

D) insulator