Consider the following statements1. In a semiconductor, the uppermost band is the valence band2. All semiconductors are electrically neutral3. With increase of temperature the resistivity of semiconductor decreases4. Addition of a small amount of impurity of a III or V group elements to a pure semiconductor increases its resistivity Choose the correct statements

Consider the following statements1. In a semiconductor, the uppermost

1.	Consider the following statements 1. In a semiconductor, the uppermost band is the valence band 2. All semiconductors are electrically neutral 3. With increase of temperature the resistivity of semiconductor decreases 4. Addition of a small amount of impurity of a III or V group elements to a pure semiconductor increases its resistivity Choose the correct statements
A.	1 and 2
B.	2 and 3
C.	3 and 4
D.	1 and 4
Answer» C. 3 and 4