Suppose you have a numeric vector with elements $1,2,$ and $3,$ in that order. Call this vector

$x.$

Suppose you also have a numeric vector with elements $4$ and $5,$ in that order. Call this vector

$y.$

What would the result of $x+y$ be$?$

Select one:

a$.$ an error

b$.567$

c$.577$

d$.456$