What is the output of the following program?

bool a $=$ true;

bool b $=$ false;

bool c $=$ false;

bool d $=$ true;

if $($a $||$ b && c $||$ d$)$

$\{$

cout $<<$A$<<$ endl;

$\}$

else if $($a && b $||$ c && d$)$

$\{$

cout $<<$B$<<$ endl;

$\}$

else

$\{$

cout $<<"$C$"<<$ endl;

$\}$