If-else statement for 5 Conditions in PHP

I have a scenario where I have to match all possible conditions for 5 variables with the if-else statement, the value of variables can be either 0 or 1, for example

if($a === 0 && $b === 0 && $c === 0 && $d === 0 && $e === 0) { 
    echo 'case_1';
} else if ($a === 1 && $b === 1 && $c === 1 && $d === 1 && $e === 1) {
    echo 'case_2';
} else if ($a === 0 && $b === 1 && $c === 1 && $d === 1 && $e === 1) {
    echo 'case_3';
} else if ($a === 0 && $b === 0 && $c === 1 && $d === 1 && $e === 1) {
    echo 'case_4';
} else if ($a === 0 && $b === 0 && $c === 0 && $d === 1 && $e === 1) {
    echo 'case_5';
} else if ($a === 0 && $b === 0 && $c === 0 && $d === 0 && $e === 1) {
    echo 'case_6';
} else if ($a === 1 && $b === 0 && $c === 0 && $d === 0 && $e === 0) {
    echo 'case_7';
} 

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There could be dozens of such conditions and managing it becomes complicated, so I want to know if there is any better and robust method to achieve this?

Update:

Variables could be alphanumeric as well,

$none = 'none'; // Default value

if($a === $none && $b === $none && $c === $none && $d === $none && $e === $none) { 
    echo 'case_1';
} else if ($a === 1 && $b === 1 && $c === 1 && $d === 1 && $e === 1) {
    echo 'case_2';
} else if ($a === $none && $b === 1 && $c === 1 && $d === 1 && $e === 1) {
    echo 'case_3';
} else if ($a === $none && $b === $none && $c === 1 && $d === 1 && $e === 1) {
    echo 'case_4';
} else if ($a === $none && $b === $none && $c === $none && $d === 1 && $e === 1) {
    echo 'case_5';
} else if ($a === $none && $b === $none && $c === $none && $d === $none && $e === 1) {
    echo 'case_6';
} else if ($a === 1 && $b === $none && $c === $none && $d === $none && $e === $none) {
    echo 'case_7';
} 

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