Which one of the following choices will change all occurrences of the string "Up" to "Down" in a scalar variable?

Which one of the following choices will change all occurrences of the string “Up” to “Down” in a
scalar variable?

A.
$status = s/Down/Up/g;

B.
$status =~ g/Up/Down/s;

C.
$status =~ s/Up/Down/I;

D.
$status =~ s/Up/Down/g;