dframe.drop$\_$duplicates$([\text{'}$key$1\text{'}])$ will:

Select one:

a$.$ drop duplicates based on the column 'key$1\text{'}$ retaining the first and last values of each duplicate entry.

b$.$ drop duplicates based on the column 'key$1\text{'}$ retaining the last value of each duplicate entry.

c$.$ drop duplicates based on the column 'key$1\text{'}$ retaining the first value of each duplicate entry.

d$.$ drop duplicates based on the column 'key$1\text{'}$ retaining none of the values of each duplicate entry.