In the following list of statements regarding a DataFrame df, one or more statements are correct. Can you identify all the correct statements? a. Every time we call df. set_index(), the old index will be discarded.
b. Every time we call df. set_index(), the old index will be set as a new column.
c. Every time we call df. reset_index(), the old index will be discarded.
d. Every time we call df. reset_index(), the old index will be set as a new column.