CMFAS CGI Commercial Liability Insurance question: consultant lets a claims-made PI policy lapse

A consultant lets a claims-made PI policy lapse when closing the business, then a claim about old advice arrives. What is the practical danger, and what guards against it?

• A There is no danger, because occurrence rules apply once a claims-made policy lapses
• B Past errors go uncovered unless run-off cover or an extended reporting period is bought
• C The old insurer must still respond, because the advice was given while it was on risk
• D The retroactive date automatically extends the reporting period after the business closes