def fRec$1($ch$)$:

$$ if $($ch $>=\text{'}$a$\text{'})$ and $($ch $<=\text{'}$h$\text{'})$:

$$ ch$=$cord$($ch$)$

$$ fRec$1($ch$)$

$$ print$($ch $,$ end $="")$

$$ else:

$$ print$()$

def cord$($ch$)$:

$$ return chr$($ord$($ch$)+1)$

What is the output of fRec$1(\text{'}$d$\text{'})$:

$1.$ defg

$2.$ efgh

$3.$ ihgfe

$4.$ hgfe