Answer: Python Puzzler #791

The answer is B. The program prints:

mango
What the program prints
Checked by running the program for real.

Why?

A negative position counts from the end: -1 is the last item, -2 the one before it. So -1 means item number 1 from the end.

Trace table

A trace table follows the program step by step. Here’s this one:

positionnegative positionitem
0-4carrot
1-3apple
2-2plum
3-1mango

The code again

basket = ["carrot", "apple", "plum", "mango"]
print(basket[-1])

Try it: change one number in the program and predict the new output before you run it.