How do you install Express.js in a Node.js project? a. None of the above b. Using the npm install express command c. Using the npm add express command d. Including it in the HTML file

The correct answer is b. "Using the npm install express command". Here are the steps to install Express.js in a Node.js project:

1. First, you need to have Node.js and npm (node package manager) installed on your computer. You can download Node.js from the official website and npm comes bundled with it.

2. Open your terminal or command prompt.

3. Navigate to the directory where you want to create your new Node.js project.

4. Run the command npm init to create a new Node.js project. This will create a package.json file in your project directory.

5. Now, you can install Express.js by running the command npm install express. This command will install Express.js in your project and add it to the dependencies in your package.json file.

6. Now, Express.js is installed in your project and you can start using it by requiring it in your Node.js files with const express = require('express');.

Option c, "Using the npm add express command", is not correct because the correct npm command to add a package to a Node.js project is npm install.

Option d, "Including it in the HTML file", is not correct because Express.js is a server-side framework and cannot be included in an HTML file.

Option a, "None of the above", is not correct because the correct answer is included in the options.