What keyword is used to define a function in PHP?

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 will be the output of the following PHP code?

<?php
function outer() {
function inner() {
echo 'Inner function';
}
}
inner();
?>

A). Inner function

B). Function does not exist: inner

C). Undefined function: inner

D). Function inner() { echo 'Inner function'; }

Which PHP feature allows defining functions within other functions?

A). Nested functions

B). Inner functions

C). Enclosed functions

D). Internal functions

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

What will be the output of the following PHP code?

<?php
function uppercase($str) {
return strtoupper($str);
}
echo uppercase('hello');
?>

A). HELLO

B). hello

C). Uppercase

D). Undefined function: uppercase

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

What is the significance of default parameter values in PHP functions?

A). Default parameter values are required for all parameters in a function

B). Default parameter values allow specifying multiple default values for a parameter

C). Default parameter values allow parameters to be optional

D). Default parameter values allow specifying the data type of parameters

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 will be the output of the following PHP code?

<?php
function add($a, $b) {
return $a + $b;
}
$result = add(5, 3);
echo $result;
?>

A). 8

B). add(5, 3)

C). function add($a, $b) {
return $a + $b;
}

D). $a + $b

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

A). vararg

B). args

C). params

D). ...$args