If \(243^x\cdot 463^y=n,\) where \(x\) and \(y\) are positive integers, what is the units digit of \(n?\)

[Vincen]

If \(243^x\cdot 463^y=n,\) where \(x\) and \(y\) are positive integers, what is the units digit of \(n?\)

(1) \(x + y = 7\)

(2) \(x = 4\)

Answer: A

Source: Manhattan GMAT