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

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 PHP function is used to return a value from a function and terminate its execution?

A). return

B). exit

C). break

D). continue

Which PHP feature allows defining functions with variable-length argument lists?

A). Dynamic functions

B). Variable arguments

C). Varargs

D). All of the above

Which PHP keyword is used to pass a function as an argument to another function?

A). Dynamic functions

B). Anonymous functions

C). Callbacks

D). All of the above

Which PHP feature allows defining functions within other functions?

A). Inner functions

B). Enclosed functions

C). Nested functions

D). All of the above

What is 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

Which keyword is used to define default parameter values in PHP functions?

A). default

B). var

C). const

D). None of the above

What will be the output of the following PHP code?
<?php
function sum($a, $b = 5) {
return $a + $b;
}
echo sum(3);
?

A). 3

B). 8

C). 5

D). Function call will result in an error

What will be 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!'; }

What is the purpose of passing arguments to a function in PHP?

A). To specify the return value of the function

B). To allow the function to accept input data

C). To define the function name

D). To terminate the execution of the function