Explain Custom Activities.
In addition to the standard activities available within the base activity library, you can make new activities to meet exact business needs. Creating custom activities may be needed to support a particular application that you require to integrate with WF. Custom activities are generally created by attributes and inheritance. You can make two types of custom activities, base and composite. You can make basic custom activity by inheriting the Activity class and custom composite activity by inheriting the composite Activity class or a derived type.