Mark the tick against the correct answer in the following:

Mark the tick against the correct answer in the following:

$\left|\begin{array}{ccc}1 & 1 & 1 \\ 1 & 1+x & 1 \\ 1 & 1 & 1+y\end{array}\right|=?$

A. $(x+y)$

B. $(x-y)$

C. $x y$

D. none of these