We have a dataframe or with a column "Description" containing text descriptions of products. We want to create a new binary variable, "discount keyword," indicating whether each description contains the word "discount."

Which code is correct?

df$[\text{'}$discount$\_$Keyword'$]=($df$[\text{'}$Description$\text{'}]==$ 'discount'$)$

df$[\text{'}$discount$\_$Keyword'$]=$ df$[\text{'}$Description$\text{'}].$str$.$contains$(\text{'}$discount$)$

df$[\text{'}$discount$\_$Keyword'$]=$ df$[\text{'}$Description$\text{'}].$contains$(\text{'}$discount$,\text{'}$ case $=$ False$)$

df$[\text{'}$discount$\_$Keyword'$]=$ df$[\text{'}$Description$\text{'}].$contains$(\text{'}$discount$\text{'})$