What is the output of the following code? 1st = [7, 8] for v in range(2): 1st.insert(-1, 1st[v]) print(1st) a. [8, 7, 8,71 b. [7, 8, 7, 8] Oc17,7,7, 8] O d. 17, 3, 8, 81 (Choose the best answer). In Python a control structure is a. A data structure for storing multiple values. O b. A mechanism to alter the flow of control during the program execution O c. A way to control input devices like a keyboard. O d. A method that allows the end user to control what happens before the program starts