What is the most likely explanation for the use of applets in an Internet application?

They improve the performance of the web server and network.

An applet is a JAVA program that is sent over the network from the web server, through a web browser, to the client machine. Then the code is run on the machine. Since the server does not run the program and the output is not sent over the network, the performance on the web server and network, over which the server and client are connected, drastically improves through the use of applets. Performance improvement is more important than other things. Since JAVA virtual machine (JVM) is embedded in most web browsers, the applet download through the web browser runs on the client machine from the web browser, not from the web server, making choice D incorrect.