The correct implementation of theCheckPaymentProcessorclass must adhere to thePaymentProcessorinterface. To accomplish this:
* Use theimplementskeyword to signify that theCheckPaymentProcessorclass is implementing thePaymentProcessorinterface.
* Define thepaymethod in theCheckPaymentProcessorclass, as it is required by thePaymentProcessorinterface.
* Thepaymethod must match the method signature defined in thePaymentProcessorinterface (void pay (Decimal amount)).
Explanation of Option D:
* It usesimplements PaymentProcessorto correctly indicate that the class adheres to the interface.
* Thepaymethod is properly implemented with the required method signature and includes a placeholder for functional code.
Other Options:
* Option A: Thepaymethod is not implemented correctly (no method body).
* Option B: Incorrect use ofextendsinstead ofimplements(interfaces are implemented, not extended).
* Option C: Same issue as Option B, with a slight variation in formatting.