Which PHP keyword is used to check if a function exists before calling it?

What will be the output of the following PHP code?

<?php
$greet = function($name) {
return 'Hello, $name!';
};
echo $greet('John');
?>

A). Hello, John!

B). Hello, $name!

C). function($name) {
return 'Hello, $name!';
}

D). John

What is the output of the following PHP code?

<?php
function multiply(...$args) {
$result = 1;
foreach ($args as $value) {
$result *= $value;
}
return $result;
}
echo multiply(2, 3, 4);
?>

A). 24

B). 9

C). 6

D). 2

Which of the following statements about return types in PHP functions is true?

A). PHP functions must always have a return type

B). PHP functions can have a return type specified using the 'returns' keyword

C). PHP functions can have a return type specified using the 'return' keyword

D). PHP functions can have a return type declared using type declarations

Which PHP feature allows defining functions within other functions?

A). Nested functions

B). Inner functions

C). Enclosed functions

D). Internal functions

Which PHP feature allows defining functions without specifying their names?

A). Anonymous functions

B). Dynamic functions

C). Global functions

D). Static functions

Which of the following statements is true about function names in PHP?

A). Function names are case-sensitive

B). Function names must start with a dollar sign ($)

C). Function names cannot contain numbers

D). Function names can contain spaces

What is the purpose of the return statement in PHP functions?

A). To terminate the function execution

B). To output a value from the function and terminate its execution

C). To define the function name

D). To declare a variable within the function

Which PHP keyword is used to declare a variable-length argument list in a function?

A). vararg

B). args

C). params

D). ...$args

What is the output of the following PHP code?

<?php
function greet() {
echo 'Hello, World!';
}
if (function_exists('greet')) {
greet();
} else {
echo 'Function does not exist';
}
?>

A). Hello, World!

B). Function does not exist

C). Undefined function: greet

D). Function greet() { echo 'Hello, World!'; }

Which of the following statements about variable scope in PHP functions is true?

A). Variables defined inside a function have global scope

B). Variables defined outside a function have local scope

C). Variables defined inside a function have local scope

D). Variables defined outside a function have global scope