Assertion : In a radioactive disintegration, an electron is emitted by the nucleus.
Reason : Electrons are always present inside the nucleus.
A. If both (A) and (R ) are correct and (R ) is the correct explanation for (A).
B. If both (A) and (R ) are correct but (R ) is not the correct explanation for (A )
C. If both (A) and (R ) are incorrect.
D. If both (A) and (R ) are incorrect.