TIMTOWTDI:

use strict;
package Question::Loaded;
use vars ('@ISA');
@ISA = ('Question');
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or

package Question::Open;
@ISA = ('Question');

use strict;
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or

package Question::MillionDollar;
use strict;
our @ISA = ('Question'); # if (perl -v >= 5.6)
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and there are other ways, too. it's a matter of style.

Edit by tye: Note that use strict can appear before the package line but that putting use vars before the package line will cause the file to fail to compile while putting our before the package line will not work in less obvious ways.