Which of the following is valid C$++$ code that prints out $"$no one is here" when the variable people is zero?

Which of the following is valid C$++$ code that prints out $"$no one is here" when the variable people is zero?

if $($people $==0)$

cout $<<"$no one is here";

cond $($people $==0)$

cout $<<"$no one is here";

cout $<<"$no one is here" if $($people $==0)$;

when $($people $==0)$

cout $<<"$no one is here";