What will be the output of the following Python code?

lst=[[1,2],[3,4]]
print(sum(lst,[]))

A. list() B. [] C. empty_list() D. list[]

A. Returns the length of the list B. Converts the list to lowercase C. Converts the list to uppercase D. Removes the last element

A. append() B. add() C. insert() D. extend()

A. Creates a new list B. Converts a list to a tuple C. Converts a string to a list D. Creates a tuple