The debugger statement programmatically creates a breakpoint in the code. To "step into each function execution," the developer must pause the code before the first function is called. Placing the debugger statement on line 03 accomplishes this. When the code pauses, the developer can use the debugging tools' "Step into" command to enter the findSubTotal function. Upon returning from it, execution will pause at the next line, allowing the developer to then step into addTax, and subsequently addTip. This is the only option that facilitates stepping into all three functions sequentially from a single breakpoint.

A. Using the debugger command on line 05 is too late. It only allows stepping into the addTip function, as findSubTotal and addTax have already executed.

C. The console.trace() method outputs the function call stack to the console but does not pause execution, which is required for stepping into functions.

D. Wrapping a function in console.log() only prints its return value. It does not pause execution or provide a mechanism to step into the function's code.

1. Mozilla Developer Network (MDN) Web Docs: The debugger statement is an official part of the ECMAScript specification. The MDN documentation states

"The debugger statement invokes any available debugging functionality... If no debugging functionality is available

this statement has no effect. The purpose of the debugger statement is to stop the execution of code at a specific point." This supports using debugger to create a breakpoint from which one can step into subsequent code.

Source: MDN Web Docs

debugger statement. Section: "Syntax".

2. Salesforce Lightning Web Components Developer Guide: In the context of JavaScript development for Salesforce (relevant to CRT-600)

the official documentation recommends using browser developer tools and the debugger statement for debugging. It explains how breakpoints pause execution

allowing for inspection and stepping through code.

Source: Salesforce Developers

Lightning Web Components Dev Guide

"Debug Your Code". Section: "Debug JavaScript".

3. Google Chrome for Developers Documentation: This is an authoritative source on using debugging tools. It describes the "Step into next function call" action

which is only available when execution is paused at a breakpoint

such as one created by a debugger statement.

Source: Chrome for Developers

JavaScript debugging reference. Section: "Step through code".