In the given reaction
`._z X^A rarr ._(z+1)Y^A rarr ._(z-1) K^(A - 4) rarr ._(z-1) K^(A - 4)`
Radioactive radiations are emitted in the sequence.

Options

A. `alpha, beta, gamma`
B. `beta, alpha, gamma`
C. `gamma, alpha, beta`
D. `beta, gamma, alpha`

Answer

B

Explanation

`""_(Z)^(A)P rarr ""_(Z+1)^(A)Q`
Atomic number increases by one, so `beta`-particle emission occurs.
`""_(Z+1)^(A)Q rarr ""_(Z-1)^(A-4)R`
The atomic number decreases by two (from Z + 1 to Z-1) and mass number decreases by four, so `alpha`-particle emission occurs.
`""_(Z-1)^(A-4)Q rarr ""_(Z-1)^(A-4)R`
No change in atomic number or mass number , so `gamma`-particle is emitted.