According to the Green Logistics textbook, "green logistics" is ________.
1) the study of the environmental effects of all the activities involved in the transport, storage and handling of digital products
2) the study of the environmental effects of all the activities involved in the transport, storage and handling of physical products
3) the study of the environmental effects of all the activities involved in the transport, storage and handling of both digital and physical products
4) the study of the environmental effects of all the activities involved in the transport, storage and handling of services