In the OSI model, what does the application layer do$?$ a$.)$ It transforms a raw transmission facility into a line that appears free of undetected transmission errors to the network layer. b$.)$ Deals with transmitting raw bits over a communication channel. c$.)$ This layer actively interacts with the operating system or application when the user decides to transfer files, read messages, or perform network$-$related activities. d$.)$ It controls the operation of the subnet which are identifiable parts of the network.