The lone pair of nitrogen in benzylamine (C6H5CH2NH2) is not involved in delocalization and remains available for donation. However, in the other compounds provided, the lone pair of nitrogen participates in delocalization, rendering them unavailable for donation, as depicted below.

The most basic compound among the given compounds is benzylamine.
In the given reaction sequence, the structure of Y would be:

Consider the following sequence of reactions : 
Molar mass of the product formed (A) is ______ g mol\(^{-1}\).