Imagine we create a pandas series using the below code. What is one simple way to retrieve the value $0\mathrm{.}5$ from the series?

import pandas as pd

df $=$ pd$.$ Series $0\mathrm{.}75,0\mathrm{.}25,1\mathrm{.}00,\mathrm{.}50,$

index $\text{'},\text{'}b\text{'},\text{'}[$:$c^{\text{'}},d^{\text{'}}\})$

df

$\text{'}]$

df$[\text{'}$d$\text{'}]$

df$[\text{'}$loc$\text{'}]$

df$[\text{'}$b$\text{'}]$

df$.$ find $[\mathrm{.}50]$

$\text{'}$a$\text{'}]$

df$[$iloc$=.5]$