To rectify this issue, you should use the npm prune --production command. This command removes unnecessary devDependencies from your node_modules directory, ensuring that only production dependencies are included in the build. Options (1) and (4) are not recommended because manually removing or upgrading devDependencies can be error-prone. Option (2) doesn't directly address the issue, and Webpack is typically used for bundling rather than dependency management.

In Express.js, you can define optional route parameters by using the ? symbol after the parameter name, like /route/:param?. This makes the parameter optional, allowing it to match both routes with and without that parameter. The other options do not represent the correct way to define optional route parameters in Express.js.

When working with file operations in Node.js using the fs module, handling asynchronous errors is crucial. Asynchronous file operations can fail due to various reasons such as file not found, permission issues, or disk full errors. Proper error handling ensures data integrity and prevents unexpected crashes in your application.

Optimizing database queries can significantly reduce response time by minimizing the number of database calls, reducing data retrieval, and improving the efficiency of data fetching, ultimately leading to faster responses. The other options either misrepresent the impact of query optimization or provide irrelevant information.

To publish a package to the NPM registry, you should use the npm publish command. This command packages and uploads your module to the NPM registry, making it available for others to use and install. Options 1, 3, and 4 are not valid commands for publishing packages and might lead to errors.

To send JSON data as a response using the http module in Node.js, you should use response.write(JSON.stringify(jsonData)). This method writes the JSON data as a string to the response. The other options are not valid methods for sending JSON data in the http module.

In EJS, you can include partial views using the <%- include('partial') %> syntax. This allows you to reuse and insert content from other EJS files into your main template, helping you create modular and maintainable views. The other options are not the correct syntax for including partials in EJS.

The response.end() method is used to end the response process in an HTTP server. It finalizes the response and sends it to the client. The other options are not valid methods for ending the response.

To install a specific version of a package using npm, you should use the npm install @ command. This allows you to specify the exact version you want to install. The other options do not provide the same functionality or may not work as expected.

In arrow functions, the value of 'this' is inherited from the surrounding lexical context, which means it refers to the 'this' value of the containing function or block. Unlike regular functions, arrow functions do not have their own 'this' binding.

A primary feature of testing frameworks like Mocha or Jest is Test Automation. These frameworks allow developers to write and run automated tests to verify that their code works correctly. This includes unit tests, integration tests, and more.

The primary role of the app object in an Express application is to handle routing and middleware functions. It defines the routes for handling different HTTP requests (GET, POST, etc.) and can use middleware to add functionality to these routes, such as authentication or error handling. The other options do not accurately describe the role of the app object in Express.