Behavior of non-strict global code The script does not begin with a ' use strict ' directive at the top level, so the global code (outside any function) runs in non-strict (sloppy) mode.

Line 01: x = 3.14; In non-strict mode, assigning to an undeclared identifier (no var, let, or const) creates an implicit global variable. So after line 01, x exists and equals 3.14.

Line 08: z = x; This also runs in non-strict mode. Since x is already defined (from line 01), z is set to 3.14. Therefore, statement B is correct: z is equal to 3.14.

Scope of ' use strict ' inside a function The line:

' use strict ' ;

inside myFunction is a directive prologue for that function, not for the entire file. This means:

Strict mode applies only within the body of myFunction , from the directive to the end of that function.

It does not retroactively affect code before the function or code outside of it.

Therefore:

Statement A is incorrect: ' use strict ' is not “hoisted” to affect the whole file. It only affects the function body.

Statement C is incorrect: strict mode does not apply from line 04 to the end of the file; it only applies within myFunction, not to global lines like 01, 08, or 09.

Execution of myFunction in strict mode When myFunction is called on line 09:

function myFunction() {

' use strict ' ;

y = x;

}

Within this function:

Strict mode is active for its body.

In strict mode, assigning to an undeclared variable (like y here) is not allowed and results in a ReferenceError at runtime.

So line 05:

y = x;

throws a ReferenceError because y is not declared with var, let, or const.

Therefore, statement E is correct: line 05 throws an error.

Why statement D is considered correct Statement D says: ' use strict ' has an effect only on line 05.

In terms of execution in this specific code:

The only executable statement in myFunction that is affected by strict mode is the assignment on line 05.

The directive itself on line 04 is not a “normal” runtime operation; it is a directive that sets the mode.

There are no other statements inside the function that behave differently under strict mode; only the line that assigns to the undeclared variable shows a strict-mode effect.

So, describing the practical execution behavior of this snippet, strict mode manifests its effect only on line 05, making statement D correct in this context.

Summary of each option:

A: Incorrect – strict does not apply to all lines in the file.

B: Correct – z becomes 3.14 in non-strict global code.

C: Incorrect – strict does not affect code outside the function.

D: Correct – in this code, the only behavioral effect of strict mode is on line 05.

E: Correct – line 05 throws a ReferenceError due to assignment to undeclared y under strict mode.

JavaScript knowledge references (descriptive, no links):

In non-strict (sloppy) mode, assigning to an undeclared identifier creates a global variable.

' use strict ' inside a function body enables strict mode for that function only.

In strict mode, assigning to an undeclared variable results in a ReferenceError.

Directive prologues ( ' use strict ' ) affect only their containing function or script, not other scopes.

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