When a small amount of impurity atoms are added to a semiconductor, then generally its resistivity:

Holes are charge carriers in

$A$ semiconductor doped with a donor impurity is

Statement-$I$: By doping silicon semiconductor with pentavalent material,the electron density increases.
Statement-$II$: The $n$-type semiconductor has a net negative charge.
In the light of the above statements,choose the most appropriate answer from the options given below:

$A$ donor atom in a semiconductor has a loosely bound electron. The orbit of this electron is considerably affected by the semiconductor material but behaves in many ways like an electron orbiting a hydrogen nucleus. Given that the electron has an effective mass of $0.07 \, m_e$,where $m_e$ is the mass of the free electron,and the space in which it moves has a permittivity of $13 \, \varepsilon_0$,then the radius of the electron's lowermost energy orbit will be close to ................. $\mathring{A}$ (take the Bohr radius of the hydrogen atom as $0.53 \mathring{A}$).

In the energy band diagram of a material shown in the figure,the open circles and filled circles denote holes and electrons,respectively. The material is: