Based on the class BCity in the last question, write a new Java class named BSF City for modeling Better Smoke-Free Cities with the following requirements. a) This BSFCity class is a public subclass of the given class BCity. This class has a specific instance field of string type, named sFreeRule, representing a specific Smoke-Free rule governing the Better Smoke-Free city. It has one constructor with the same set of parameters as its direct superclass. The constructor body simply calls the corresponding constructor of its superclass properly. Based on the class BCity in the last question, write a new Java class named BSF City for modeling Better Smoke-Free Cities with the following requirements. a) This BSFCity class is a public subclass of the given class BCity. This class has a specific instance field of string type, named sFreeRule, representing a specific Smoke-Free rule governing the Better Smoke-Free city. It has one constructor with the same set of parameters as its direct superclass. The constructor body simply calls the corresponding constructor of its superclass properly