A) ( \alpha = \frac{N_A}{N_B}B) ( \alpha = \frac{N_P}{N_D}C) ( \alpha = \frac{N_0}{N_B}D) ( \alpha = \frac{N_D}{N_P})
A) ( \alpha = \frac{N_A}{N_B}
B) ( \alpha = \frac{N_P}{N_D}
C) ( \alpha = \frac{N_0}{N_B}
D) ( \alpha = \frac{N_D}{N_P})