The correct choice is (d) Modularity
Explanation: The Closure Compiler is a tool for making JavaScript download and runs faster. Instead of compiling from a source language to machine code, it compiles from JavaScript to better JavaScript. The closure compiler is highly beneficial in terms of:
Efficiency: The Closure Compiler reduces the size of your JavaScript files and makes them more efficient, helping your application to load faster and reducing your bandwidth needs.
Code checking: The Closure Compiler provides warnings for illegal JavaScript and warnings for potentially dangerous operations, helping you to produce JavaScript that is less buggy and easier to maintain.