The minimal pair $/$bed$/$ and $/$b$$d$/$ proves that:

$/$b$/$ and $/$d$/$ are different phonemes in English

$\frac{?}{?}\frac{}{?}$ and $\frac{?}{?}\frac{}{?}$ are different phonemes in English

$\frac{?}{?}\frac{}{?}$ and $\frac{?}{?}\frac{}{?}$ are different phonemes in all languages

$/$b$/$ and $/$d$/$ are different phonemes in all languages