question_answer

In the sequence of following nuclear reactions \[_{92}{{X}^{238}}\xrightarrow{-\alpha }Y\xrightarrow{-\beta }Z\xrightarrow{-\beta }L{{\xrightarrow{-n\alpha }}_{84}}{{M}^{218}}\]                 The value of \[n\] will be                                              [MP PMT 1999]

A)                 3             

B)                 4

C)                 5             

D)                 6