Given the following code:

string $=$ 'success'

d $=\{\}$

for ch in letter:

if ch not in d:

d$[$ch$]=1$

else:

d$[$ch$]+=1$

What is the value of d$?$

Question $4$ options:

$\{\text{'}$s$\text{'}$ : $3,\text{'}$u$\text{'}$:$1,\text{'}$c$\text{'}$:$2,\text{'}$ e$\text{'}$:$1\}$

$\{\text{'}$r$\text{'}$: $2,\text{'}$u$\text{'}$: $1,\text{'}$n$\text{'}$: $2,\text{'}$e$\text{'}$: $1\}$

$\{\text{'}$s: $1,\text{'}$u$\text{'}$: $1,\text{'}$c$\text{'}$: $1,\text{'}$c$\text{'}$: $1,\text{'}$e$\text{'}$:$1,\text{'}$s$\text{'}$: $2\}$

$\{\text{'}$s$\text{'}$ : $1,\text{'}$u$\text{'}$:$1,\text{'}$c$\text{'}$:$2,\text{'}$ e$\text{'}$:$1,\text{'}$s$\text{'}$:$1\}$