Which is the correct syntax of defining a default argument value in PHP?

Question

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function function_name(type $argument_name = value) { /* function body*/ }

Admin · Answer

function function_name(type $argument_name : value) { /* function body*/ }

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function function_name(type $argument_name , value) { /* function body*/ }

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All of the above

Q. Which is the correct syntax of defining a default argument value in PHP?