The compound shown is a hydrocarbon yet has a noticeable dipole moment. The best explanation is that

1. Athe five-membered ring gains a partial negative charge and the seven-membered ring a partial positive charge, each ring approaching a 6 pi electron system
2. Bit contains polar C-H bonds that do not cancel
3. Cthe seven-membered ring gains a partial negative charge and the five-membered ring a partial positive charge
4. Dit contains a carbonyl group